diff --git a/src/libraries/System.Private.CoreLib/src/System/IO/Strategies/WindowsFileStreamStrategy.cs b/src/libraries/System.Private.CoreLib/src/System/IO/Strategies/WindowsFileStreamStrategy.cs
index c178c5e47daa65..8c33d75aeebdd6 100644
--- a/src/libraries/System.Private.CoreLib/src/System/IO/Strategies/WindowsFileStreamStrategy.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/IO/Strategies/WindowsFileStreamStrategy.cs
@@ -186,7 +186,7 @@ public sealed override long Seek(long offset, SeekOrigin origin)
             long pos = origin switch
             {
                 SeekOrigin.Begin => offset,
-                SeekOrigin.End => FileStreamHelpers.GetFileLength(_fileHandle, _path) + offset,
+                SeekOrigin.End => Length + offset,
                 _ => _filePosition + offset // SeekOrigin.Current
             };