diff --git a/src/misc1.c b/src/misc1.c
index b30b077..8588411 100644
--- a/src/misc1.c
+++ b/src/misc1.c
@@ -1932,7 +1932,7 @@
     int		c;
 {
 #if defined(FEAT_MBYTE) || defined(PROTO)
-    char_u	buf[MB_MAXBYTES];
+    char_u	buf[MB_MAXBYTES + 1];
     int		n;
 
     n = (*mb_char2bytes)(c, buf);