diff --git a/utf8.c b/utf8.c
index a83e3d38..5ba41e9a 100644
--- a/utf8.c
+++ b/utf8.c
@@ -129,7 +129,7 @@ utf8_from_data(const struct utf8_data *ud, utf8_char *uc)
 	u_int	index;
 
 	if (ud->width > 2)
-		fatalx("invalid UTF-8 width");
+		fatalx("invalid UTF-8 width: %u", ud->width);
 
 	if (ud->size > UTF8_SIZE)
 		goto fail;