diff --git a/src/string_width.gleam b/src/string_width.gleam
index b9f21cc..aa246d3 100644
--- a/src/string_width.gleam
+++ b/src/string_width.gleam
@@ -289,7 +289,7 @@ fn do_fold(
   }
 }
 
-pub fn do_fold_characters(
+fn do_fold_characters(
   options: Options,
   string: String,
   state: state,