diff --git a/src/file_storage.cpp b/src/file_storage.cpp
index e11f1f879..65c1a6add 100644
--- a/src/file_storage.cpp
+++ b/src/file_storage.cpp
@@ -290,7 +290,7 @@ namespace libtorrent
 
 		peer_request ret;
 		ret.piece = int(offset / piece_length());
-		ret.start = int(offset - ret.piece * piece_length());
+		ret.start = int(offset % piece_length());
 		ret.length = size;
 		return ret;
 	}