diff --git a/thunar/thunar-file.c b/thunar/thunar-file.c
index 1171527..941299a 100644
--- a/thunar/thunar-file.c
+++ b/thunar/thunar-file.c
@@ -3113,12 +3113,17 @@ static gint
 compare_by_name_using_number (const gchar *ap,
                               const gchar *bp)
 {
-  guint anum;
-  guint bnum;
+  gsize anum;
+  gsize bnum;
 
-  /* determine the numbers in ap and bp */
-  anum = strtoul (ap, NULL, 10);
-  bnum = strtoul (bp, NULL, 10);
+  /* up until now the numbers match. Now compare the numbers by digit
+   * count, the longest number is the largest. If the length are equal
+   * just compare this digit.
+   */
+
+  /* determine digit count in ap and bp */
+  anum = strspn (ap, "0123456789");
+  bnum = strspn (bp, "0123456789");
 
   /* compare the numbers */
   if (anum < bnum)
@@ -3126,11 +3131,10 @@ compare_by_name_using_number (const gchar *ap,
   else if (anum > bnum)
     return 1;
 
-  /* the numbers are equal, and so the higher first digit should
-   * be sorted first, i.e. 'file10' before 'file010', since we
-   * also sort 'file10' before 'file011'.
+  /* the numbers are equal in length, and so the lower first digit should
+   * be sorted first.
    */
-  return (*bp - *ap);
+  return (*ap - *bp);
 }