diff --git a/main.c b/main.c
index 2b36c4f..f41330c 100644
--- a/main.c
+++ b/main.c
@@ -72,7 +72,7 @@
 
 #define CHUNKSIZE (8<<20)    // 8 MB
 #define CACHELINE 64
-#define OUT_CHUNKSIZE (CHUNKSIZE + (CHUNKSIZE>>8) + CACHELINE)
+#define OUT_CHUNKSIZE (CHUNKSIZE + (CHUNKSIZE/255) + CACHELINE)
 #define ARCHIVE_MAGICNUMBER 0x184C2102
 #define ARCHIVE_MAGICNUMBER_SIZE 4