diff --git a/utf8.c b/utf8.c
index 8ccdf684e0784a..050fc8b3cdfdf8 100644
--- a/utf8.c
+++ b/utf8.c
@@ -206,7 +206,7 @@ int utf8_width(const char **start, size_t *remainder_p)
  * string, assuming that the string is utf8.  Returns strlen() instead
  * if the string does not look like a valid utf8 string.
  */
-int utf8_strnwidth(const char *string, size_t len, int skip_ansi)
+size_t utf8_strnwidth(const char *string, size_t len, int skip_ansi)
 {
 	const char *orig = string;
 	size_t width = 0;
@@ -224,14 +224,10 @@ int utf8_strnwidth(const char *string, size_t len, int skip_ansi)
 			width += glyph_width;
 	}
 
-	/*
-	 * TODO: fix the interface of this function and `utf8_strwidth()` to
-	 * return `size_t` instead of `int`.
-	 */
-	return cast_size_t_to_int(string ? width : len);
+	return string ? width : len;
 }
 
-int utf8_strwidth(const char *string)
+size_t utf8_strwidth(const char *string)
 {
 	return utf8_strnwidth(string, strlen(string), 0);
 }
diff --git a/utf8.h b/utf8.h
index 35df76086a6c91..cae10d5ac1f13a 100644
--- a/utf8.h
+++ b/utf8.h
@@ -7,8 +7,8 @@ typedef unsigned int ucs_char_t;  /* assuming 32bit int */
 
 size_t display_mode_esc_sequence_len(const char *s);
 int utf8_width(const char **start, size_t *remainder_p);
-int utf8_strnwidth(const char *string, size_t len, int skip_ansi);
-int utf8_strwidth(const char *string);
+size_t utf8_strnwidth(const char *string, size_t len, int skip_ansi);
+size_t utf8_strwidth(const char *string);
 int is_utf8(const char *text);
 int is_encoding_utf8(const char *name);
 int same_encoding(const char *, const char *);