diff --git a/free.c b/free.c
index 6c72138c..f86ab951 100644
--- a/free.c
+++ b/free.c
@@ -148,7 +148,7 @@ static const char *scale_size(unsigned long size, int flags, struct commandline_
 
 	/* human readable output */
 	up = nextup;
-	for (i = 1; up[0] != '0'; i++, up++) {
+	for (i = 1; up[0] != 0; i++, up++) {
 		switch (i) {
 		case 1:
 			if (4 >= snprintf(buf, sizeof(buf), "%ld%c", (long)size * 1024, *up))