file.go | 2 +-

diff --git a/file.go b/file.go
index 4775b4ff0e8d55e3781971c53af5297a2958b93b..6925101c637f79b9587ce3add782bbcb6641e6d8 100644
--- a/file.go
+++ b/file.go
@@ -180,5 +180,5 @@ func (f *File) endPieceIndex() pieceIndex {
 	if f.t.usualPieceSize() == 0 {
 		return 0
 	}
-	return pieceIndex((f.offset+f.length-1)/int64(f.t.usualPieceSize())) + 1
+	return pieceIndex((f.offset + f.length + int64(f.t.usualPieceSize()) - 1) / int64(f.t.usualPieceSize()))
 }