diff --git a/app/Actions/Conversions/CreateConversionJobAction.php b/app/Actions/Conversions/CreateConversionJobAction.php
index a5388ce..052eb4c 100644
--- a/app/Actions/Conversions/CreateConversionJobAction.php
+++ b/app/Actions/Conversions/CreateConversionJobAction.php
@@ -4,20 +4,27 @@
 
 namespace App\Actions\Conversions;
 
+use App\Contracts\Billing\CreditLedger;
+use App\Enums\ConversionCreditChargeStatus;
 use App\Enums\ConversionStatus;
 use App\Enums\FileFormat;
+use App\Exceptions\Billing\InsufficientCreditsException;
 use App\Jobs\ProcessConversionJob;
+use App\Models\ConversionCreditCharge;
 use App\Models\ConversionJob;
 use App\Models\FileRecord;
 use App\Models\User;
 use App\Support\Conversions\Exceptions\UnsupportedConversionException;
 use App\Support\Converters\ConverterRegistry;
 use App\Support\Converters\Exceptions\UnsupportedFormatException;
+use Illuminate\Support\Facades\DB;
 
 final class CreateConversionJobAction
 {
     public function __construct(
         private readonly ConverterRegistry $converterRegistry,
+        private readonly EstimateConversionCostAction $estimateCost,
+        private readonly CreditLedger $creditLedger,
     ) {}
 
     /**
@@ -48,19 +55,47 @@ public function handle(
 
         $normalizedOptions = $converter->validateOptions($options);
 
-        $job = ConversionJob::create([
-            'user_id' => $user->id,
-            'source_file_id' => $sourceFile->id,
-            'source_format' => $sourceFormat,
-            'target_format' => $normalizedTarget,
-            // Driver-registry key (e.g. "png_to_jpg") — distinct from the catalog
-            // Converter::key() ("png:jpg"). ConverterDriverRegistry::findOrFail()
-            // resolves drivers on this value, so it must match driver keys.
-            'converter_key' => "{$sourceFormat}_to_{$normalizedTarget}",
-            'options_json' => $normalizedOptions,
-            'status' => ConversionStatus::Queued,
-            'progress' => 0,
-        ]);
+        $cost = $this->estimateCost->handle($sourceFile, $converter, $normalizedOptions);
+
+        $balance = $this->creditLedger->balance($user);
+
+        if ($balance < $cost->amount) {
+            throw InsufficientCreditsException::make(
+                required: $cost->amount,
+                available: $balance,
+            );
+        }
+
+        // Wrap job + charge creation in a transaction so a failed charge insert
+        // cannot leave an orphan queued job. Dispatch happens after commit so
+        // the worker never picks up a job whose charge record does not exist.
+        $job = DB::transaction(function () use ($user, $sourceFile, $sourceFormat, $normalizedTarget, $normalizedOptions, $cost) {
+            $job = ConversionJob::create([
+                'user_id' => $user->id,
+                'source_file_id' => $sourceFile->id,
+                'source_format' => $sourceFormat,
+                'target_format' => $normalizedTarget,
+                // Driver-registry key (e.g. "png_to_jpg") — distinct from the catalog
+                // Converter::key() ("png:jpg"). ConverterDriverRegistry::findOrFail()
+                // resolves drivers on this value, so it must match driver keys.
+                'converter_key' => "{$sourceFormat}_to_{$normalizedTarget}",
+                'options_json' => $normalizedOptions,
+                'status' => ConversionStatus::Queued,
+                'progress' => 0,
+            ]);
+
+            ConversionCreditCharge::create([
+                'user_id' => $user->id,
+                'conversion_job_id' => $job->id,
+                'estimated_amount' => $cost->amount,
+                'captured_amount' => 0,
+                'refunded_amount' => 0,
+                'status' => ConversionCreditChargeStatus::Estimated,
+                'breakdown_json' => $cost->breakdown,
+            ]);
+
+            return $job;
+        });
 
         ProcessConversionJob::dispatch($job->id);
 
diff --git a/app/Actions/Conversions/EstimateConversionCostAction.php b/app/Actions/Conversions/EstimateConversionCostAction.php
new file mode 100644
index 0000000..3d5da39
--- /dev/null
+++ b/app/Actions/Conversions/EstimateConversionCostAction.php
@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Actions\Conversions;
+
+use App\Contracts\Billing\ConversionCostEstimator;
+use App\Data\Credits\CreditCost;
+use App\Models\FileRecord;
+use App\Support\Converters\Contracts\Converter;
+
+final class EstimateConversionCostAction
+{
+    public function __construct(
+        private readonly ConversionCostEstimator $estimator,
+    ) {}
+
+    /**
+     * @param  array<string, mixed>  $options
+     */
+    public function handle(FileRecord $file, Converter $converter, array $options = []): CreditCost
+    {
+        return $this->estimator->estimate($file, $converter, $options);
+    }
+}
diff --git a/app/Contracts/Billing/ConversionCostEstimator.php b/app/Contracts/Billing/ConversionCostEstimator.php
new file mode 100644
index 0000000..d959b72
--- /dev/null
+++ b/app/Contracts/Billing/ConversionCostEstimator.php
@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Contracts\Billing;
+
+use App\Data\Credits\CreditCost;
+use App\Models\FileRecord;
+use App\Support\Converters\Contracts\Converter;
+
+interface ConversionCostEstimator
+{
+    /**
+     * @param  array<string, mixed>  $options
+     */
+    public function estimate(FileRecord $file, Converter $converter, array $options = []): CreditCost;
+}
diff --git a/app/Data/Credits/CreditCost.php b/app/Data/Credits/CreditCost.php
new file mode 100644
index 0000000..f64369d
--- /dev/null
+++ b/app/Data/Credits/CreditCost.php
@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Data\Credits;
+
+final readonly class CreditCost
+{
+    public function __construct(
+        public int $amount,
+        public array $breakdown,
+    ) {
+        if ($this->amount < 0) {
+            throw new \InvalidArgumentException('Credit cost amount cannot be negative.');
+        }
+    }
+}
diff --git a/app/Data/Credits/CreditCostBreakdown.php b/app/Data/Credits/CreditCostBreakdown.php
new file mode 100644
index 0000000..91d51d5
--- /dev/null
+++ b/app/Data/Credits/CreditCostBreakdown.php
@@ -0,0 +1,45 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Data\Credits;
+
+final readonly class CreditCostBreakdown
+{
+    public function __construct(
+        public int $base,
+        public int $size,
+        public int $features,
+        public int $total,
+        public array $details,
+    ) {
+        if ($this->base < 0) {
+            throw new \InvalidArgumentException('Breakdown base cannot be negative.');
+        }
+        if ($this->size < 0) {
+            throw new \InvalidArgumentException('Breakdown size cannot be negative.');
+        }
+        if ($this->features < 0) {
+            throw new \InvalidArgumentException('Breakdown features cannot be negative.');
+        }
+        if ($this->total < 0) {
+            throw new \InvalidArgumentException('Breakdown total cannot be negative.');
+        }
+        if ($this->total !== ($this->base + $this->size + $this->features)) {
+            throw new \InvalidArgumentException(
+                "Breakdown total ({$this->total}) must equal base + size + features ({$this->base} + {$this->size} + {$this->features})."
+            );
+        }
+    }
+
+    public function toArray(): array
+    {
+        return [
+            'base' => $this->base,
+            'size' => $this->size,
+            'features' => $this->features,
+            'total' => $this->total,
+            'details' => $this->details,
+        ];
+    }
+}
diff --git a/app/Enums/ConversionCreditChargeStatus.php b/app/Enums/ConversionCreditChargeStatus.php
new file mode 100644
index 0000000..a9d1406
--- /dev/null
+++ b/app/Enums/ConversionCreditChargeStatus.php
@@ -0,0 +1,13 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Enums;
+
+enum ConversionCreditChargeStatus: string
+{
+    case Estimated = 'estimated';
+    case Captured = 'captured';
+    case Refunded = 'refunded';
+    case Failed = 'failed';
+}
diff --git a/app/Exceptions/Billing/UnsupportedConversionCostException.php b/app/Exceptions/Billing/UnsupportedConversionCostException.php
new file mode 100644
index 0000000..5964e93
--- /dev/null
+++ b/app/Exceptions/Billing/UnsupportedConversionCostException.php
@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Exceptions\Billing;
+
+use DomainException;
+
+final class UnsupportedConversionCostException extends DomainException
+{
+    public static function forPair(string $source, string $target): self
+    {
+        return new self("Cannot estimate cost for unsupported conversion: {$source} → {$target}.");
+    }
+}
diff --git a/app/Jobs/ProcessConversionJob.php b/app/Jobs/ProcessConversionJob.php
index ca999df..a02c787 100644
--- a/app/Jobs/ProcessConversionJob.php
+++ b/app/Jobs/ProcessConversionJob.php
@@ -5,7 +5,10 @@
 namespace App\Jobs;
 
 use App\Actions\Conversions\RecordConversionResultFileAction;
+use App\Contracts\Billing\CreditLedger;
+use App\Enums\ConversionCreditChargeStatus;
 use App\Enums\ConversionStatus;
+use App\Models\ConversionCreditCharge;
 use App\Models\ConversionJob;
 use App\Support\Conversions\ConverterDriverRegistry;
 use App\Support\Conversions\DTO\ConversionContext;
@@ -14,6 +17,7 @@
 use Illuminate\Foundation\Bus\Dispatchable;
 use Illuminate\Queue\InteractsWithQueue;
 use Illuminate\Queue\SerializesModels;
+use Illuminate\Support\Facades\DB;
 use Illuminate\Support\Str;
 use Throwable;
 
@@ -31,6 +35,7 @@ public function __construct(
     public function handle(
         ConverterDriverRegistry $drivers,
         RecordConversionResultFileAction $recorder,
+        CreditLedger $creditLedger,
     ): void {
         $job = ConversionJob::find($this->conversionJobId);
 
@@ -64,6 +69,15 @@ public function handle(
                 'progress' => 100,
                 'completed_at' => now(),
             ])->save();
+
+            // Capture credits separately — a billing failure must not undo a
+            // successful conversion, so we report and move on rather than
+            // letting the exception propagate to the failure catch block below.
+            try {
+                $this->captureCredits($job, $creditLedger);
+            } catch (Throwable $captureException) {
+                report($captureException);
+            }
         } catch (Throwable $exception) {
             $job->forceFill([
                 'status' => ConversionStatus::Failed,
@@ -72,7 +86,56 @@ public function handle(
                 'completed_at' => now(),
             ])->save();
 
+            $this->markChargeFailed($job);
+
             report($exception);
         }
     }
+
+    private function captureCredits(ConversionJob $job, CreditLedger $creditLedger): void
+    {
+        $charge = $job->creditCharge;
+
+        if ($charge === null) {
+            return;
+        }
+
+        DB::transaction(function () use ($job, $charge, $creditLedger) {
+            // Lock the charge row and verify it is still in the expected state
+            // before spending, so duplicate executions are idempotent.
+            $lockedCharge = ConversionCreditCharge::lockForUpdate()->find($charge->id);
+
+            if ($lockedCharge === null || $lockedCharge->status !== ConversionCreditChargeStatus::Estimated) {
+                return;
+            }
+
+            $creditLedger->spend(
+                user: $job->user,
+                amount: $lockedCharge->estimated_amount,
+                reason: 'conversion_completed',
+                meta: [
+                    'conversion_job_id' => $job->id,
+                    'converter_key' => $job->converter_key,
+                ],
+            );
+
+            $lockedCharge->forceFill([
+                'captured_amount' => $lockedCharge->estimated_amount,
+                'status' => ConversionCreditChargeStatus::Captured,
+            ])->save();
+        });
+    }
+
+    private function markChargeFailed(ConversionJob $job): void
+    {
+        $charge = $job->creditCharge;
+
+        if ($charge === null) {
+            return;
+        }
+
+        $charge->forceFill([
+            'status' => ConversionCreditChargeStatus::Failed,
+        ])->save();
+    }
 }
diff --git a/app/Livewire/Dashboard/DashboardConverter.php b/app/Livewire/Dashboard/DashboardConverter.php
index a657987..6469806 100644
--- a/app/Livewire/Dashboard/DashboardConverter.php
+++ b/app/Livewire/Dashboard/DashboardConverter.php
@@ -3,8 +3,11 @@
 namespace App\Livewire\Dashboard;
 
 use App\Actions\Conversions\CreateConversionJobAction;
+use App\Actions\Conversions\EstimateConversionCostAction;
 use App\Actions\Files\StoreUploadedFileAction;
 use App\Enums\ConversionStatus;
+use App\Exceptions\Billing\InsufficientCreditsException;
+use App\Exceptions\Billing\UnsupportedConversionCostException;
 use App\Exceptions\Files\FileStorageException;
 use App\Exceptions\Files\UnsupportedFileFormatException;
 use App\Exceptions\Storage\StorageLimitExceededException;
@@ -60,6 +63,8 @@ class DashboardConverter extends Component
 
     public ?string $convertError = null;
 
+    public ?int $estimatedCreditCost = null;
+
     public function updatedUpload(): void
     {
         $this->storeUpload(app(StoreUploadedFileAction::class), app(FeatureAccessService::class));
@@ -190,6 +195,18 @@ public function selectTargetFormat(string $targetFormat): void
             $this->initializeOptionsFromSchema();
         }
 
+        try {
+            $cost = app(EstimateConversionCostAction::class)->handle(
+                $this->currentFile,
+                $converter,
+                $this->options,
+            );
+            $this->estimatedCreditCost = $cost->amount;
+        } catch (UnsupportedConversionCostException|\InvalidArgumentException) {
+            // Known pricing failures — unsupported pair or misconfigured rule.
+            $this->estimatedCreditCost = null;
+        }
+
         $this->step = 'settings';
     }
 
@@ -244,6 +261,12 @@ public function convert(): void
             $this->convertError = 'This conversion is not supported. Please choose a different format.';
             $this->step = 'format';
 
+            return;
+        } catch (InsufficientCreditsException $e) {
+            $this->convertError = 'Not enough credits. This conversion requires '
+                .($this->estimatedCreditCost ?? '?')
+                .' credit(s). Please top up your balance.';
+
             return;
         } catch (Throwable) {
             $this->convertError = 'Something went wrong. Please try again.';
@@ -338,6 +361,7 @@ private function resetTargetSelection(): void
         $this->optionsSchema = [];
         $this->options = [];
         $this->optionsByTarget = [];
+        $this->estimatedCreditCost = null;
     }
 
     public function getCurrentJobProperty(): ?ConversionJob
diff --git a/app/Models/ConversionCreditCharge.php b/app/Models/ConversionCreditCharge.php
new file mode 100644
index 0000000..dd36b28
--- /dev/null
+++ b/app/Models/ConversionCreditCharge.php
@@ -0,0 +1,45 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Models;
+
+use App\Enums\ConversionCreditChargeStatus;
+use Database\Factories\ConversionCreditChargeFactory;
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+class ConversionCreditCharge extends Model
+{
+    /** @use HasFactory<ConversionCreditChargeFactory> */
+    use HasFactory;
+
+    protected $fillable = [
+        'user_id',
+        'conversion_job_id',
+        'estimated_amount',
+        'captured_amount',
+        'refunded_amount',
+        'status',
+        'breakdown_json',
+    ];
+
+    protected $casts = [
+        'status' => ConversionCreditChargeStatus::class,
+        'breakdown_json' => 'array',
+        'estimated_amount' => 'integer',
+        'captured_amount' => 'integer',
+        'refunded_amount' => 'integer',
+    ];
+
+    public function user(): BelongsTo
+    {
+        return $this->belongsTo(User::class);
+    }
+
+    public function conversionJob(): BelongsTo
+    {
+        return $this->belongsTo(ConversionJob::class);
+    }
+}
diff --git a/app/Models/ConversionJob.php b/app/Models/ConversionJob.php
index 2cb5d6d..d337a65 100644
--- a/app/Models/ConversionJob.php
+++ b/app/Models/ConversionJob.php
@@ -10,6 +10,7 @@
 use Illuminate\Database\Eloquent\Factories\HasFactory;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\Relations\HasOne;
 use Illuminate\Support\Carbon;
 
 /**
@@ -82,6 +83,11 @@ public function resultFile(): BelongsTo
         return $this->belongsTo(FileRecord::class, 'result_file_id');
     }
 
+    public function creditCharge(): HasOne
+    {
+        return $this->hasOne(ConversionCreditCharge::class);
+    }
+
     public function isCompleted(): bool
     {
         return $this->status === ConversionStatus::Completed;
diff --git a/app/Providers/AppServiceProvider.php b/app/Providers/AppServiceProvider.php
index 985c259..8960068 100644
--- a/app/Providers/AppServiceProvider.php
+++ b/app/Providers/AppServiceProvider.php
@@ -2,9 +2,11 @@
 
 namespace App\Providers;
 
+use App\Contracts\Billing\ConversionCostEstimator;
 use App\Contracts\Billing\CreditLedger;
 use App\Models\User;
 use App\Observers\UserObserver;
+use App\Services\Billing\ConfigDrivenConversionCostEstimator;
 use App\Services\Billing\DatabaseCreditLedger;
 use Illuminate\Support\ServiceProvider;
 
@@ -16,6 +18,7 @@ class AppServiceProvider extends ServiceProvider
     public function register(): void
     {
         $this->app->bind(CreditLedger::class, DatabaseCreditLedger::class);
+        $this->app->bind(ConversionCostEstimator::class, ConfigDrivenConversionCostEstimator::class);
     }
 
     /**
diff --git a/app/Services/Billing/ConfigDrivenConversionCostEstimator.php b/app/Services/Billing/ConfigDrivenConversionCostEstimator.php
new file mode 100644
index 0000000..26beeaf
--- /dev/null
+++ b/app/Services/Billing/ConfigDrivenConversionCostEstimator.php
@@ -0,0 +1,77 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Services\Billing;
+
+use App\Contracts\Billing\ConversionCostEstimator;
+use App\Data\Credits\CreditCost;
+use App\Data\Credits\CreditCostBreakdown;
+use App\Exceptions\Billing\UnsupportedConversionCostException;
+use App\Models\FileRecord;
+use App\Support\Converters\Contracts\Converter;
+
+final class ConfigDrivenConversionCostEstimator implements ConversionCostEstimator
+{
+    /**
+     * @param  array<string, mixed>  $options
+     */
+    public function estimate(FileRecord $file, Converter $converter, array $options = []): CreditCost
+    {
+        $source = $converter->sourceFormat();
+        $target = $converter->targetFormat();
+
+        if ($this->isImage($source) && $this->isImage($target)) {
+            return $this->makeCost('image_to_image', $file, $converter);
+        }
+
+        if ($this->isImage($source) && $this->isPdf($target)) {
+            return $this->makeCost('image_to_pdf', $file, $converter);
+        }
+
+        throw UnsupportedConversionCostException::forPair($source, $target);
+    }
+
+    private function makeCost(string $rule, FileRecord $file, Converter $converter): CreditCost
+    {
+        $configKey = "conversion_costs.rules.{$rule}.base";
+        $raw = config($configKey);
+
+        if ($raw === null || ! is_numeric($raw)) {
+            throw new \InvalidArgumentException(
+                "Missing or invalid pricing rule: '{$configKey}'. Expected a numeric value."
+            );
+        }
+
+        $base = (int) $raw;
+
+        $breakdown = new CreditCostBreakdown(
+            base: $base,
+            size: 0,
+            features: 0,
+            total: $base,
+            details: [
+                'rule' => $rule,
+                'source_format' => $converter->sourceFormat(),
+                'target_format' => $converter->targetFormat(),
+                'converter_key' => $converter->key(),
+                'file_size_bytes' => $file->size_bytes,
+            ],
+        );
+
+        return new CreditCost(
+            amount: $breakdown->total,
+            breakdown: $breakdown->toArray(),
+        );
+    }
+
+    private function isImage(string $format): bool
+    {
+        return in_array($format, config('conversion_costs.groups.image', []), true);
+    }
+
+    private function isPdf(string $format): bool
+    {
+        return in_array($format, config('conversion_costs.groups.pdf', []), true);
+    }
+}
diff --git a/config/conversion_costs.php b/config/conversion_costs.php
new file mode 100644
index 0000000..436c29c
--- /dev/null
+++ b/config/conversion_costs.php
@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+return [
+    'rules' => [
+        'image_to_image' => [
+            'base' => 1,
+            'size' => 0,
+            'features' => [],
+        ],
+        'image_to_pdf' => [
+            'base' => 2,
+            'size' => 0,
+            'features' => [],
+        ],
+    ],
+
+    'groups' => [
+        'image' => ['png', 'jpg', 'jpeg', 'webp'],
+        'pdf' => ['pdf'],
+    ],
+];
diff --git a/database/factories/ConversionCreditChargeFactory.php b/database/factories/ConversionCreditChargeFactory.php
new file mode 100644
index 0000000..74d7688
--- /dev/null
+++ b/database/factories/ConversionCreditChargeFactory.php
@@ -0,0 +1,55 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Database\Factories;
+
+use App\Enums\ConversionCreditChargeStatus;
+use App\Models\ConversionCreditCharge;
+use App\Models\User;
+use Illuminate\Database\Eloquent\Factories\Factory;
+
+/**
+ * @extends Factory<ConversionCreditCharge>
+ */
+class ConversionCreditChargeFactory extends Factory
+{
+    protected $model = ConversionCreditCharge::class;
+
+    public function definition(): array
+    {
+        return [
+            'user_id' => User::factory(),
+            'conversion_job_id' => null,
+            'estimated_amount' => 1,
+            'captured_amount' => 0,
+            'refunded_amount' => 0,
+            'status' => ConversionCreditChargeStatus::Estimated,
+            'breakdown_json' => null,
+        ];
+    }
+
+    public function estimated(): static
+    {
+        return $this->state([
+            'status' => ConversionCreditChargeStatus::Estimated,
+            'captured_amount' => 0,
+        ]);
+    }
+
+    public function captured(): static
+    {
+        return $this->state(fn (array $attributes) => [
+            'status' => ConversionCreditChargeStatus::Captured,
+            'captured_amount' => $attributes['estimated_amount'],
+        ]);
+    }
+
+    public function failed(): static
+    {
+        return $this->state([
+            'status' => ConversionCreditChargeStatus::Failed,
+            'captured_amount' => 0,
+        ]);
+    }
+}
diff --git a/database/factories/ConversionJobFactory.php b/database/factories/ConversionJobFactory.php
index 36120d0..3d31fc1 100644
--- a/database/factories/ConversionJobFactory.php
+++ b/database/factories/ConversionJobFactory.php
@@ -37,6 +37,16 @@ public function definition(): array
         ];
     }
 
+    public function pngToJpg(): static
+    {
+        return $this->state([
+            'source_format' => 'png',
+            'target_format' => 'jpg',
+            'converter_key' => 'png_to_jpg',
+            'options_json' => ['quality' => 'high'],
+        ]);
+    }
+
     public function queued(): static
     {
         return $this->state(['status' => ConversionStatus::Queued, 'progress' => 0]);
diff --git a/database/factories/FileRecordFactory.php b/database/factories/FileRecordFactory.php
index 49960ac..d5a9dd3 100644
--- a/database/factories/FileRecordFactory.php
+++ b/database/factories/FileRecordFactory.php
@@ -19,6 +19,26 @@ public function expired(): static
         return $this->state(['expires_at' => now()->subHour()]);
     }
 
+    public function png(): static
+    {
+        return $this->state([
+            'original_name' => fake()->slug().'.png',
+            'stored_path' => 'uploads/'.fake()->uuid().'.png',
+            'mime_type' => 'image/png',
+            'extension' => 'png',
+        ]);
+    }
+
+    public function jpg(): static
+    {
+        return $this->state([
+            'original_name' => fake()->slug().'.jpg',
+            'stored_path' => 'uploads/'.fake()->uuid().'.jpg',
+            'mime_type' => 'image/jpeg',
+            'extension' => 'jpg',
+        ]);
+    }
+
     public function definition(): array
     {
         $extension = fake()->randomElement(['png', 'jpg', 'webp', 'pdf']);
diff --git a/database/migrations/2026_06_02_123052_create_conversion_credit_charges_table.php b/database/migrations/2026_06_02_123052_create_conversion_credit_charges_table.php
new file mode 100644
index 0000000..0c3b117
--- /dev/null
+++ b/database/migrations/2026_06_02_123052_create_conversion_credit_charges_table.php
@@ -0,0 +1,31 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    public function up(): void
+    {
+        Schema::create('conversion_credit_charges', function (Blueprint $table) {
+            $table->id();
+            $table->foreignId('user_id')->constrained()->cascadeOnDelete();
+            $table->foreignId('conversion_job_id')->nullable()->constrained()->nullOnDelete();
+            $table->unsignedInteger('estimated_amount');
+            $table->unsignedInteger('captured_amount')->default(0);
+            $table->unsignedInteger('refunded_amount')->default(0);
+            $table->string('status');
+            $table->json('breakdown_json')->nullable();
+            $table->timestamps();
+
+            $table->index(['user_id', 'status']);
+            $table->index('conversion_job_id');
+        });
+    }
+
+    public function down(): void
+    {
+        Schema::dropIfExists('conversion_credit_charges');
+    }
+};
diff --git a/database/migrations/2026_06_02_133059_add_unique_constraint_to_conversion_credit_charges_conversion_job_id.php b/database/migrations/2026_06_02_133059_add_unique_constraint_to_conversion_credit_charges_conversion_job_id.php
new file mode 100644
index 0000000..49e25b0
--- /dev/null
+++ b/database/migrations/2026_06_02_133059_add_unique_constraint_to_conversion_credit_charges_conversion_job_id.php
@@ -0,0 +1,30 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    /**
+     * Run the migrations.
+     */
+    public function up(): void
+    {
+        Schema::table('conversion_credit_charges', function (Blueprint $table) {
+            $table->dropIndex('conversion_credit_charges_conversion_job_id_index');
+            $table->unique('conversion_job_id');
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::table('conversion_credit_charges', function (Blueprint $table) {
+            $table->dropUnique('conversion_credit_charges_conversion_job_id_unique');
+            $table->index('conversion_job_id');
+        });
+    }
+};
diff --git a/resources/views/livewire/dashboard/dashboard-converter.blade.php b/resources/views/livewire/dashboard/dashboard-converter.blade.php
index cefcec1..e47819b 100644
--- a/resources/views/livewire/dashboard/dashboard-converter.blade.php
+++ b/resources/views/livewire/dashboard/dashboard-converter.blade.php
@@ -168,10 +168,16 @@ class="flex items-start gap-3 rounded-[var(--ca-radius-md)] border border-[var(-
                 @include('livewire.dashboard.dashboard-converter.partials.dynamic-options-form')
 
                 <div
-                    data-testid="estimated-cost-placeholder"
+                    data-testid="estimated-cost"
                     class="flex items-center justify-between gap-4 rounded-[var(--ca-radius-md)] border border-[var(--ca-border)] bg-[var(--ca-surface-muted)]/40 px-4 py-3">
                     <span class="text-sm font-semibold text-[var(--ca-text)]">Estimated cost</span>
-                    <p class="text-sm text-[var(--ca-muted)]">Credit cost will be calculated before conversion.</p>
+                    @if ($estimatedCreditCost !== null)
+                        <p class="text-sm font-semibold text-[var(--ca-text)]">
+                            {{ $estimatedCreditCost }} {{ $estimatedCreditCost === 1 ? 'credit' : 'credits' }}
+                        </p>
+                    @else
+                        <p class="text-sm text-[var(--ca-muted)]">Credit cost will be calculated before conversion.</p>
+                    @endif
                 </div>
 
                 <div class="flex justify-end">
@@ -264,6 +270,13 @@ class="inline-flex w-full items-center justify-center gap-2 rounded-[var(--ca-ra
                     <x-button variant="ghost" size="sm" wire:click="goToSettingsStep">← Back</x-button>
                 </div>
 
+                @if ($convertError)
+                    <div class="rounded-[var(--ca-radius-md)] border border-red-200 bg-red-50 px-4 py-3">
+                        <p class="text-sm font-semibold text-red-700">Not enough credits</p>
+                        <p class="mt-1 text-sm text-red-600">{{ $convertError }}</p>
+                    </div>
+                @endif
+
                 <div class="rounded-[var(--ca-radius-md)] border border-dashed border-[var(--ca-border)] bg-[var(--ca-surface-muted)]/40 px-6 py-8 text-center">
                     <p class="text-base font-semibold text-[var(--ca-text)]">
                         Ready to convert {{ strtoupper($file->extension) }} to {{ strtoupper($selectedTargetFormat) }}
diff --git a/tests/Fakes/Converters/FakeUnsupportedConverter.php b/tests/Fakes/Converters/FakeUnsupportedConverter.php
new file mode 100644
index 0000000..d080998
--- /dev/null
+++ b/tests/Fakes/Converters/FakeUnsupportedConverter.php
@@ -0,0 +1,53 @@
+<?php
+
+namespace Tests\Fakes\Converters;
+
+use App\Support\Converters\Contracts\Converter;
+
+final class FakeUnsupportedConverter implements Converter
+{
+    public function __construct(
+        private readonly string $source,
+        private readonly string $target,
+    ) {}
+
+    public function key(): string
+    {
+        return "{$this->source}_to_{$this->target}";
+    }
+
+    public function sourceFormat(): string
+    {
+        return $this->source;
+    }
+
+    public function targetFormat(): string
+    {
+        return $this->target;
+    }
+
+    public function label(): string
+    {
+        return strtoupper($this->target);
+    }
+
+    public function description(): string
+    {
+        return 'Unsupported conversion';
+    }
+
+    public function optionsSchema(): array
+    {
+        return [];
+    }
+
+    public function validateOptions(array $options): array
+    {
+        return $options;
+    }
+
+    public function isRecommended(): bool
+    {
+        return false;
+    }
+}
diff --git a/tests/Feature/Actions/CreateConversionJobActionCreditTest.php b/tests/Feature/Actions/CreateConversionJobActionCreditTest.php
new file mode 100644
index 0000000..0784dc5
--- /dev/null
+++ b/tests/Feature/Actions/CreateConversionJobActionCreditTest.php
@@ -0,0 +1,71 @@
+<?php
+
+declare(strict_types=1);
+
+use App\Actions\Conversions\CreateConversionJobAction;
+use App\Contracts\Billing\CreditLedger;
+use App\Exceptions\Billing\InsufficientCreditsException;
+use App\Jobs\ProcessConversionJob;
+use App\Models\ConversionJob;
+use App\Models\FileRecord;
+use App\Models\User;
+use Illuminate\Support\Facades\Queue;
+
+it('does not create conversion job when user has insufficient credits', function () {
+    Queue::fake();
+
+    $user = User::factory()->create();
+    $user->creditAccount->forceFill(['balance' => 1])->save();
+
+    $file = FileRecord::factory()->png()->for($user)->create();
+
+    app(CreateConversionJobAction::class)->handle(
+        user: $user,
+        sourceFile: $file,
+        targetFormat: 'pdf',
+        options: [],
+    );
+})->throws(InsufficientCreditsException::class);
+
+it('does not dispatch queue job when credits are insufficient', function () {
+    Queue::fake();
+
+    $user = User::factory()->create();
+    $user->creditAccount->forceFill(['balance' => 1])->save();
+
+    $file = FileRecord::factory()->png()->for($user)->create();
+
+    try {
+        app(CreateConversionJobAction::class)->handle(
+            user: $user,
+            sourceFile: $file,
+            targetFormat: 'pdf',
+            options: [],
+        );
+    } catch (InsufficientCreditsException) {
+        // expected
+    }
+
+    expect(ConversionJob::query()->count())->toBe(0);
+    Queue::assertNothingPushed();
+});
+
+it('creates conversion job when user has enough credits', function () {
+    Queue::fake();
+
+    $user = User::factory()->create();
+    app(CreditLedger::class)->grant($user, 10, 'test');
+
+    $file = FileRecord::factory()->png()->for($user)->create();
+
+    $job = app(CreateConversionJobAction::class)->handle(
+        user: $user,
+        sourceFile: $file,
+        targetFormat: 'jpg',
+        options: [],
+    );
+
+    expect($job->exists)->toBeTrue();
+    expect(ConversionJob::query()->count())->toBe(1);
+    Queue::assertPushed(ProcessConversionJob::class);
+});
diff --git a/tests/Feature/Actions/EstimateConversionCostActionTest.php b/tests/Feature/Actions/EstimateConversionCostActionTest.php
new file mode 100644
index 0000000..86fa436
--- /dev/null
+++ b/tests/Feature/Actions/EstimateConversionCostActionTest.php
@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+use App\Actions\Conversions\EstimateConversionCostAction;
+use App\Models\FileRecord;
+use App\Support\Converters\ConverterRegistry;
+
+it('estimates conversion cost through application action', function () {
+    $file = FileRecord::factory()->png()->create();
+    $converter = app(ConverterRegistry::class)->find('png', 'jpg');
+
+    $cost = app(EstimateConversionCostAction::class)->handle($file, $converter, []);
+
+    expect($cost->amount)->toBe(1);
+});
+
+it('estimates pdf conversion cost through application action', function () {
+    $file = FileRecord::factory()->png()->create();
+    $converter = app(ConverterRegistry::class)->find('png', 'pdf');
+
+    $cost = app(EstimateConversionCostAction::class)->handle($file, $converter, []);
+
+    expect($cost->amount)->toBe(2);
+});
diff --git a/tests/Feature/Conversion/ProcessConversionJobRealDriverTest.php b/tests/Feature/Conversion/ProcessConversionJobRealDriverTest.php
index b879dc1..75b37c9 100644
--- a/tests/Feature/Conversion/ProcessConversionJobRealDriverTest.php
+++ b/tests/Feature/Conversion/ProcessConversionJobRealDriverTest.php
@@ -3,6 +3,7 @@
 declare(strict_types=1);
 
 use App\Actions\Conversions\RecordConversionResultFileAction;
+use App\Contracts\Billing\CreditLedger;
 use App\Enums\ConversionStatus;
 use App\Jobs\ProcessConversionJob;
 use App\Models\ConversionJob;
@@ -40,6 +41,7 @@
     (new ProcessConversionJob($job->id))->handle(
         app(ConverterDriverRegistry::class),
         app(RecordConversionResultFileAction::class),
+        app(CreditLedger::class),
     );
 
     $fresh = $job->fresh();
@@ -76,6 +78,7 @@
     (new ProcessConversionJob($job->id))->handle(
         app(ConverterDriverRegistry::class),
         app(RecordConversionResultFileAction::class),
+        app(CreditLedger::class),
     );
 
     $fresh = $job->fresh();
@@ -113,6 +116,7 @@
     (new ProcessConversionJob($job->id))->handle(
         app(ConverterDriverRegistry::class),
         app(RecordConversionResultFileAction::class),
+        app(CreditLedger::class),
     );
 
     $fresh = $job->fresh();
diff --git a/tests/Feature/ConversionFlowTest.php b/tests/Feature/ConversionFlowTest.php
index 72e20b2..4a4963a 100644
--- a/tests/Feature/ConversionFlowTest.php
+++ b/tests/Feature/ConversionFlowTest.php
@@ -3,6 +3,7 @@
 declare(strict_types=1);
 
 use App\Actions\Conversions\RecordConversionResultFileAction;
+use App\Contracts\Billing\CreditLedger;
 use App\Jobs\ProcessConversionJob;
 use App\Livewire\Dashboard\DashboardConverter;
 use App\Models\ConversionJob;
@@ -34,6 +35,7 @@
     (new ProcessConversionJob($job->id))->handle(
         app(ConverterDriverRegistry::class),
         app(RecordConversionResultFileAction::class),
+        app(CreditLedger::class),
     );
 
     $component
diff --git a/tests/Feature/Jobs/ProcessConversionJobCreditTest.php b/tests/Feature/Jobs/ProcessConversionJobCreditTest.php
new file mode 100644
index 0000000..f793364
--- /dev/null
+++ b/tests/Feature/Jobs/ProcessConversionJobCreditTest.php
@@ -0,0 +1,88 @@
+<?php
+
+declare(strict_types=1);
+
+use App\Actions\Conversions\RecordConversionResultFileAction;
+use App\Contracts\Billing\CreditLedger;
+use App\Enums\ConversionCreditChargeStatus;
+use App\Jobs\ProcessConversionJob;
+use App\Models\ConversionCreditCharge;
+use App\Models\ConversionJob;
+use App\Models\User;
+use App\Support\Conversions\ConverterDriverRegistry;
+use Illuminate\Support\Facades\Storage;
+use Tests\Fakes\Conversions\FakeConverterDriver;
+
+it('captures credits after successful conversion', function () {
+    Storage::fake('local');
+
+    $user = User::factory()->create();
+    $user->creditAccount->forceFill(['balance' => 10])->save();
+
+    $job = ConversionJob::factory()
+        ->pngToJpg()
+        ->queued()
+        ->for($user)
+        ->create();
+
+    ConversionCreditCharge::factory()
+        ->for($user)
+        ->for($job, 'conversionJob')
+        ->create([
+            'estimated_amount' => 1,
+            'captured_amount' => 0,
+            'status' => ConversionCreditChargeStatus::Estimated,
+        ]);
+
+    app()->instance(
+        ConverterDriverRegistry::class,
+        new ConverterDriverRegistry([new FakeConverterDriver('png_to_jpg')]),
+    );
+
+    (new ProcessConversionJob($job->id))->handle(
+        app(ConverterDriverRegistry::class),
+        app(RecordConversionResultFileAction::class),
+        app(CreditLedger::class),
+    );
+
+    expect(app(CreditLedger::class)->balance($user))->toBe(9);
+    expect($job->creditCharge->fresh()->status)->toBe(ConversionCreditChargeStatus::Captured);
+    expect($job->creditCharge->fresh()->captured_amount)->toBe(1);
+});
+
+it('does not spend credits when conversion fails', function () {
+    Storage::fake('local');
+
+    $user = User::factory()->create();
+    $user->creditAccount->forceFill(['balance' => 10])->save();
+
+    $job = ConversionJob::factory()
+        ->pngToJpg()
+        ->queued()
+        ->for($user)
+        ->create();
+
+    ConversionCreditCharge::factory()
+        ->for($user)
+        ->for($job, 'conversionJob')
+        ->create([
+            'estimated_amount' => 1,
+            'captured_amount' => 0,
+            'status' => ConversionCreditChargeStatus::Estimated,
+        ]);
+
+    app()->instance(
+        ConverterDriverRegistry::class,
+        new ConverterDriverRegistry([new FakeConverterDriver('png_to_jpg', shouldFail: true)]),
+    );
+
+    (new ProcessConversionJob($job->id))->handle(
+        app(ConverterDriverRegistry::class),
+        app(RecordConversionResultFileAction::class),
+        app(CreditLedger::class),
+    );
+
+    expect(app(CreditLedger::class)->balance($user))->toBe(10);
+    expect($job->creditCharge->fresh()->status)->toBe(ConversionCreditChargeStatus::Failed);
+    expect($job->creditCharge->fresh()->captured_amount)->toBe(0);
+});
diff --git a/tests/Feature/Jobs/ProcessConversionJobTest.php b/tests/Feature/Jobs/ProcessConversionJobTest.php
index 001ed6e..1dad88f 100644
--- a/tests/Feature/Jobs/ProcessConversionJobTest.php
+++ b/tests/Feature/Jobs/ProcessConversionJobTest.php
@@ -3,6 +3,7 @@
 declare(strict_types=1);
 
 use App\Actions\Conversions\RecordConversionResultFileAction;
+use App\Contracts\Billing\CreditLedger;
 use App\Enums\ConversionStatus;
 use App\Jobs\ProcessConversionJob;
 use App\Models\ConversionJob;
@@ -43,6 +44,7 @@
     (new ProcessConversionJob($conversionJob->id))->handle(
         app(ConverterDriverRegistry::class),
         app(RecordConversionResultFileAction::class),
+        app(CreditLedger::class),
     );
 
     $fresh = $conversionJob->fresh();
@@ -85,6 +87,7 @@
     (new ProcessConversionJob($conversionJob->id))->handle(
         app(ConverterDriverRegistry::class),
         app(RecordConversionResultFileAction::class),
+        app(CreditLedger::class),
     );
 
     $fresh = $conversionJob->fresh();
@@ -118,6 +121,7 @@
     (new ProcessConversionJob($conversionJob->id))->handle(
         app(ConverterDriverRegistry::class),
         app(RecordConversionResultFileAction::class),
+        app(CreditLedger::class),
     );
 
     expect($conversionJob->fresh()->status)->toBe(ConversionStatus::Completed);
diff --git a/tests/Feature/Livewire/DashboardConverterCostTest.php b/tests/Feature/Livewire/DashboardConverterCostTest.php
new file mode 100644
index 0000000..82116c8
--- /dev/null
+++ b/tests/Feature/Livewire/DashboardConverterCostTest.php
@@ -0,0 +1,52 @@
+<?php
+
+declare(strict_types=1);
+
+use App\Livewire\Dashboard\DashboardConverter;
+use App\Models\ConversionJob;
+use App\Models\FileRecord;
+use App\Models\User;
+use Illuminate\Support\Facades\Queue;
+use Livewire\Livewire;
+
+it('shows estimated conversion cost in settings step', function () {
+    $user = User::factory()->create();
+    $file = FileRecord::factory()->png()->for($user)->create();
+
+    Livewire::actingAs($user)
+        ->test(DashboardConverter::class)
+        ->set('currentFileId', $file->id)
+        ->call('selectTargetFormat', 'pdf')
+        ->assertSee('2 credits');
+});
+
+it('shows 1 credit cost for image to image conversion', function () {
+    $user = User::factory()->create();
+    $file = FileRecord::factory()->png()->for($user)->create();
+
+    Livewire::actingAs($user)
+        ->test(DashboardConverter::class)
+        ->set('currentFileId', $file->id)
+        ->call('selectTargetFormat', 'jpg')
+        ->assertSee('1 credit');
+});
+
+it('shows insufficient credits message and does not create job', function () {
+    Queue::fake();
+
+    $user = User::factory()->create();
+    $user->creditAccount->forceFill(['balance' => 1])->save();
+
+    $file = FileRecord::factory()->png()->for($user)->create();
+
+    Livewire::actingAs($user)
+        ->test(DashboardConverter::class)
+        ->set('currentFileId', $file->id)
+        ->call('selectTargetFormat', 'pdf')
+        ->call('continueFromSettings')
+        ->call('convert')
+        ->assertSee('Not enough credits');
+
+    expect(ConversionJob::query()->count())->toBe(0);
+    Queue::assertNothingPushed();
+});
diff --git a/tests/Feature/Livewire/DashboardConverterSettingsStepTest.php b/tests/Feature/Livewire/DashboardConverterSettingsStepTest.php
index 759f810..fcc0606 100644
--- a/tests/Feature/Livewire/DashboardConverterSettingsStepTest.php
+++ b/tests/Feature/Livewire/DashboardConverterSettingsStepTest.php
@@ -85,16 +85,16 @@
         ->assertSee('Background color');
 });
 
-it('shows the estimated cost placeholder on the settings step', function () {
+it('shows the estimated cost on the settings step', function () {
     $user = User::factory()->create();
-    $file = FileRecord::factory()->for($user)->create(['extension' => 'png']);
+    $file = FileRecord::factory()->png()->for($user)->create();
 
     Livewire::actingAs($user)
         ->test(DashboardConverter::class)
         ->set('currentFileId', $file->id)
         ->call('selectTargetFormat', 'jpg')
         ->assertSee('Estimated cost')
-        ->assertSee('calculated before conversion');
+        ->assertSee('1 credit');
 });
 
 it('renders the png to jpg settings form', function () {
diff --git a/tests/Feature/Models/ConversionCreditChargeTest.php b/tests/Feature/Models/ConversionCreditChargeTest.php
new file mode 100644
index 0000000..496f145
--- /dev/null
+++ b/tests/Feature/Models/ConversionCreditChargeTest.php
@@ -0,0 +1,49 @@
+<?php
+
+declare(strict_types=1);
+
+use App\Enums\ConversionCreditChargeStatus;
+use App\Models\ConversionCreditCharge;
+use App\Models\ConversionJob;
+
+it('creates conversion credit charge record', function () {
+    $charge = ConversionCreditCharge::factory()->create([
+        'estimated_amount' => 2,
+        'captured_amount' => 0,
+        'status' => ConversionCreditChargeStatus::Estimated,
+    ]);
+
+    expect($charge->exists)->toBeTrue();
+    expect($charge->estimated_amount)->toBe(2);
+    expect($charge->captured_amount)->toBe(0);
+    expect($charge->status)->toBe(ConversionCreditChargeStatus::Estimated);
+});
+
+it('belongs to a user', function () {
+    $charge = ConversionCreditCharge::factory()->create();
+
+    expect($charge->user)->not->toBeNull();
+});
+
+it('can be linked to a conversion job', function () {
+    $charge = ConversionCreditCharge::factory()
+        ->for(ConversionJob::factory(), 'conversionJob')
+        ->create();
+
+    expect($charge->conversion_job_id)->not->toBeNull();
+    expect($charge->conversionJob)->not->toBeNull();
+});
+
+it('captured state sets captured amount equal to estimated', function () {
+    $charge = ConversionCreditCharge::factory()->create([
+        'estimated_amount' => 2,
+    ]);
+
+    $charge->forceFill([
+        'captured_amount' => $charge->estimated_amount,
+        'status' => ConversionCreditChargeStatus::Captured,
+    ])->save();
+
+    expect($charge->fresh()->status)->toBe(ConversionCreditChargeStatus::Captured);
+    expect($charge->fresh()->captured_amount)->toBe(2);
+});
diff --git a/tests/Unit/Config/ConversionCostsConfigTest.php b/tests/Unit/Config/ConversionCostsConfigTest.php
new file mode 100644
index 0000000..a4bf9d6
--- /dev/null
+++ b/tests/Unit/Config/ConversionCostsConfigTest.php
@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+it('has conversion costs config for mvp converters', function () {
+    expect(config('conversion_costs.rules.image_to_image.base'))->toBe(1);
+    expect(config('conversion_costs.rules.image_to_pdf.base'))->toBe(2);
+});
+
+it('has image format group', function () {
+    $imageFormats = config('conversion_costs.groups.image');
+
+    expect($imageFormats)->toContain('png');
+    expect($imageFormats)->toContain('jpg');
+    expect($imageFormats)->toContain('jpeg');
+    expect($imageFormats)->toContain('webp');
+});
+
+it('has pdf format group', function () {
+    $pdfFormats = config('conversion_costs.groups.pdf');
+
+    expect($pdfFormats)->toContain('pdf');
+});
diff --git a/tests/Unit/Contracts/ConversionCostEstimatorContractTest.php b/tests/Unit/Contracts/ConversionCostEstimatorContractTest.php
new file mode 100644
index 0000000..9bb8b5f
--- /dev/null
+++ b/tests/Unit/Contracts/ConversionCostEstimatorContractTest.php
@@ -0,0 +1,9 @@
+<?php
+
+declare(strict_types=1);
+
+use App\Contracts\Billing\ConversionCostEstimator;
+
+it('can resolve conversion cost estimator contract', function () {
+    expect(interface_exists(ConversionCostEstimator::class))->toBeTrue();
+});
diff --git a/tests/Unit/Data/CreditCostBreakdownTest.php b/tests/Unit/Data/CreditCostBreakdownTest.php
new file mode 100644
index 0000000..1c0f145
--- /dev/null
+++ b/tests/Unit/Data/CreditCostBreakdownTest.php
@@ -0,0 +1,65 @@
+<?php
+
+declare(strict_types=1);
+
+use App\Data\Credits\CreditCostBreakdown;
+
+it('creates credit cost breakdown dto', function () {
+    $breakdown = new CreditCostBreakdown(
+        base: 1,
+        size: 0,
+        features: 1,
+        total: 2,
+        details: ['target' => 'pdf'],
+    );
+
+    expect($breakdown->total)->toBe(2);
+    expect($breakdown->toArray()['base'])->toBe(1);
+});
+
+it('exposes all fields', function () {
+    $breakdown = new CreditCostBreakdown(
+        base: 2,
+        size: 0,
+        features: 0,
+        total: 2,
+        details: ['rule' => 'image_to_pdf'],
+    );
+
+    expect($breakdown->base)->toBe(2);
+    expect($breakdown->size)->toBe(0);
+    expect($breakdown->features)->toBe(0);
+    expect($breakdown->total)->toBe(2);
+    expect($breakdown->details)->toBe(['rule' => 'image_to_pdf']);
+});
+
+it('converts to array with all keys', function () {
+    $breakdown = new CreditCostBreakdown(
+        base: 1,
+        size: 0,
+        features: 0,
+        total: 1,
+        details: [],
+    );
+
+    $array = $breakdown->toArray();
+
+    expect($array)->toHaveKeys(['base', 'size', 'features', 'total', 'details']);
+    expect($array['total'])->toBe(1);
+});
+
+it('rejects negative base', function () {
+    new CreditCostBreakdown(base: -1, size: 0, features: 0, total: 0, details: []);
+})->throws(InvalidArgumentException::class);
+
+it('rejects negative size', function () {
+    new CreditCostBreakdown(base: 0, size: -1, features: 0, total: 0, details: []);
+})->throws(InvalidArgumentException::class);
+
+it('rejects negative features', function () {
+    new CreditCostBreakdown(base: 0, size: 0, features: -1, total: 0, details: []);
+})->throws(InvalidArgumentException::class);
+
+it('rejects negative total', function () {
+    new CreditCostBreakdown(base: 0, size: 0, features: 0, total: -1, details: []);
+})->throws(InvalidArgumentException::class);
diff --git a/tests/Unit/Data/CreditCostTest.php b/tests/Unit/Data/CreditCostTest.php
new file mode 100644
index 0000000..541baae
--- /dev/null
+++ b/tests/Unit/Data/CreditCostTest.php
@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+use App\Data\Credits\CreditCost;
+
+it('creates credit cost dto', function () {
+    $cost = new CreditCost(amount: 2, breakdown: []);
+
+    expect($cost->amount)->toBe(2);
+    expect($cost->breakdown)->toBe([]);
+});
+
+it('creates credit cost with breakdown data', function () {
+    $breakdown = ['base' => 2, 'total' => 2];
+    $cost = new CreditCost(amount: 2, breakdown: $breakdown);
+
+    expect($cost->amount)->toBe(2);
+    expect($cost->breakdown)->toBe($breakdown);
+});
+
+it('rejects negative amount', function () {
+    new CreditCost(amount: -1, breakdown: []);
+})->throws(InvalidArgumentException::class);
+
+it('allows zero amount', function () {
+    $cost = new CreditCost(amount: 0, breakdown: []);
+
+    expect($cost->amount)->toBe(0);
+});
diff --git a/tests/Unit/Services/ConversionCostEstimatorResolutionTest.php b/tests/Unit/Services/ConversionCostEstimatorResolutionTest.php
new file mode 100644
index 0000000..d8aeeb7
--- /dev/null
+++ b/tests/Unit/Services/ConversionCostEstimatorResolutionTest.php
@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+use App\Contracts\Billing\ConversionCostEstimator;
+use App\Services\Billing\ConfigDrivenConversionCostEstimator;
+
+it('resolves conversion cost estimator implementation from container', function () {
+    $estimator = app(ConversionCostEstimator::class);
+
+    expect($estimator)->toBeInstanceOf(ConfigDrivenConversionCostEstimator::class);
+});
diff --git a/tests/Unit/Services/ConversionCostEstimatorTest.php b/tests/Unit/Services/ConversionCostEstimatorTest.php
new file mode 100644
index 0000000..c75fff3
--- /dev/null
+++ b/tests/Unit/Services/ConversionCostEstimatorTest.php
@@ -0,0 +1,78 @@
+<?php
+
+declare(strict_types=1);
+
+use App\Contracts\Billing\ConversionCostEstimator;
+use App\Exceptions\Billing\UnsupportedConversionCostException;
+use App\Models\FileRecord;
+use App\Support\Converters\ConverterRegistry;
+use Tests\Fakes\Converters\FakeUnsupportedConverter;
+
+it('estimates image to image conversion as one credit', function () {
+    $file = FileRecord::factory()->png()->make(['user_id' => 1]);
+    $converter = app(ConverterRegistry::class)->find('png', 'jpg');
+
+    $cost = app(ConversionCostEstimator::class)->estimate($file, $converter, []);
+
+    expect($cost->amount)->toBe(1);
+});
+
+it('estimates jpg to webp conversion as one credit', function () {
+    $file = FileRecord::factory()->jpg()->make(['user_id' => 1]);
+    $converter = app(ConverterRegistry::class)->find('jpg', 'webp');
+
+    $cost = app(ConversionCostEstimator::class)->estimate($file, $converter, []);
+
+    expect($cost->amount)->toBe(1);
+});
+
+it('estimates image to pdf conversion as two credits', function () {
+    $file = FileRecord::factory()->png()->make(['user_id' => 1]);
+    $converter = app(ConverterRegistry::class)->find('png', 'pdf');
+
+    $cost = app(ConversionCostEstimator::class)->estimate($file, $converter, []);
+
+    expect($cost->amount)->toBe(2);
+});
+
+it('estimates jpg to pdf conversion as two credits', function () {
+    $file = FileRecord::factory()->jpg()->make(['user_id' => 1]);
+    $converter = app(ConverterRegistry::class)->find('jpg', 'pdf');
+
+    $cost = app(ConversionCostEstimator::class)->estimate($file, $converter, []);
+
+    expect($cost->amount)->toBe(2);
+});
+
+it('estimates png to webp conversion as one credit', function () {
+    $file = FileRecord::factory()->png()->make(['user_id' => 1]);
+    $converter = app(ConverterRegistry::class)->find('png', 'webp');
+
+    $cost = app(ConversionCostEstimator::class)->estimate($file, $converter, []);
+
+    expect($cost->amount)->toBe(1);
+});
+
+it('rejects unsupported cost estimation', function () {
+    $file = FileRecord::factory()->png()->make(['user_id' => 1]);
+    $converter = new FakeUnsupportedConverter('png', 'mp3');
+
+    app(ConversionCostEstimator::class)->estimate($file, $converter, []);
+})->throws(UnsupportedConversionCostException::class);
+
+it('returns stable cost breakdown', function () {
+    $file = FileRecord::factory()->png()->make(['user_id' => 1]);
+    $converter = app(ConverterRegistry::class)->find('png', 'pdf');
+
+    $cost = app(ConversionCostEstimator::class)->estimate($file, $converter, []);
+
+    expect($cost->breakdown)->toHaveKeys([
+        'base',
+        'size',
+        'features',
+        'total',
+        'details',
+    ]);
+
+    expect($cost->breakdown['total'])->toBe($cost->amount);
+});