diff --git a/lib/charset.c b/lib/charset.c
index 91cbe87..de201cf 100644
--- a/lib/charset.c
+++ b/lib/charset.c
@@ -407,7 +407,7 @@
 
 	if (!src)
 		return NULL;
-	len = (u16_strlen(src) + 1) * sizeof(u16);
+	len = u16_strsize(src);
 	new = malloc(len);
 	if (!new)
 		return NULL;