metainfo/builder.go | 2 +-

diff --git a/metainfo/builder.go b/metainfo/builder.go
index 96df1939732165c3d13e9dbcc93ebbbd0aa11bcd..72683bb564fd7d246906b2978d752c102b2d93bf 100644
--- a/metainfo/builder.go
+++ b/metainfo/builder.go
@@ -304,7 +304,7 @@ 		}
 
 		// prepare files for reading
 		fr := files_reader{files: b.files}
-		npieces := b.total_size/b.piece_length + 1
+		npieces := (b.total_size + b.piece_length - 1) / b.piece_length
 		b.pieces = make([]byte, 20*npieces)
 		hashed := int64(0)