diff --git a/src/Apache.Arrow/C/CArrowArrayImporter.cs b/src/Apache.Arrow/C/CArrowArrayImporter.cs
index c454380e..2dc4adba 100644
--- a/src/Apache.Arrow/C/CArrowArrayImporter.cs
+++ b/src/Apache.Arrow/C/CArrowArrayImporter.cs
@@ -470,7 +470,10 @@ private ArrowBuffer[] ImportFixedWidthBuffers(CArrowArray* cArray, int bitWidth)
                 int length = checked((int)cArray->offset + (int)cArray->length);
                 int valuesLength;
                 if (bitWidth >= 8)
-                    valuesLength = checked(length * bitWidth / 8);
+                {
+                    Debug.Assert(bitWidth % 8 == 0);
+                    valuesLength = checked((int)((ulong)length * (ulong)bitWidth / 8ul));
+                }
                 else
                     valuesLength = checked((int)BitUtility.RoundUpToMultipleOf8(length) / 8);