diff --git a/src/dirlisting.c b/src/dirlisting.c
index 2d9a5da..62df779 100644
--- a/src/dirlisting.c
+++ b/src/dirlisting.c
@@ -48,7 +48,7 @@ const char* format_size(off_t s) {
   }
 
   if(divisions == 0) {
-    sprintf(buf, "%lu B", s);
+    sprintf(buf, "%lli B", (long long)s);
   } else {
     sprintf(buf, "%.2f %ciB", fs, prefixes[divisions]);
   }