diff --git a/Src/utils.c b/Src/utils.c
index 733f570..32e7dc6 100644
--- a/Src/utils.c
+++ b/Src/utils.c
@@ -5341,7 +5341,12 @@ mb_metastrlenend(char *ptr, int width, char *eptr)
 	    inchar = *ptr;
 	ptr++;
 
-	if (complete && (inchar >= 0 && inchar <= 0x7f)) {
+        /*
+         * 0x7f is all ones except for top bit in binary,
+         * this will check if inchar is in range 0 .. 127
+         * inclusive, regardless of char signedness
+         */
+	if (complete && (inchar & 0x7f) == inchar) {
 	    /*
 	     * We rely on 7-bit US-ASCII as a subset, so skip
 	     * multibyte handling if we have such a character.