diff --git a/apps/shell/shell-vars.c b/apps/shell/shell-vars.c
index b28834f4a..14b484923 100644
--- a/apps/shell/shell-vars.c
+++ b/apps/shell/shell-vars.c
@@ -90,7 +90,7 @@ PROCESS_THREAD(shell_var_process, ev, data)
 {
   int i;
   int j;
-  char numbuf[32];
+  char numbuf[40];
   
   PROCESS_BEGIN();