diff --git a/fx/string.c b/fx/string.c
index 83d6d9e..cf0b0a9 100644
--- a/fx/string.c
+++ b/fx/string.c
@@ -513,7 +513,8 @@ static enum fx_status remove_ansi(
 	memmove(removal_start, excess_src, excess_length);
 	s[new_str_len] = '\0';
 
-	str->s_len = new_str_len;
+	str->s_len -= length;
+	str->s_codepoints -= length;
 
 	return FX_SUCCESS;
 }