diff --git a/usr.bin/jot/jot.c b/usr.bin/jot/jot.c
index 34ec76b55f4f..088903f86674 100644
--- a/usr.bin/jot/jot.c
+++ b/usr.bin/jot/jot.c
@@ -480,7 +480,9 @@ getformat(void)
 			else if (*p == '%' && *(p+1) == '%')
 				p++;
 			else if (*p == '%' && !*(p+1)) {
-				strcat(format, "%");
+				if (strlcat(format, "%", sizeof(format)) >=
+				    sizeof(format))
+					errx(1, "-w word too long");
 				break;
 			}
 	}