diff --git a/table.c b/table.c
index 5c41c89..e996570 100644
--- a/table.c
+++ b/table.c
@@ -510,9 +510,8 @@ int
 visible_length_plain(char *str)
 {
     int len = 0, max_len = 0;
-    char *strz = str + strlen(str);
 
-    while (str < strz) {
+    while (*str) {
 	if (*str == '\t') {
 	    do {
 		len++;