diff --git a/reference/datetime/datetime/diff.xml b/reference/datetime/datetime/diff.xml
index 0dd33c498b..986d852377 100644
--- a/reference/datetime/datetime/diff.xml
+++ b/reference/datetime/datetime/diff.xml
@@ -68,7 +68,7 @@
 $datetime1 = new DateTime('2009-10-11');
 $datetime2 = new DateTime('2009-10-13');
 $interval = $datetime1->diff($datetime2);
-echo $interval->format('%R%d days');
+echo $interval->format('%R%a days');
 ?>
 ]]>
    </programlisting>
@@ -79,7 +79,7 @@ echo $interval->format('%R%d days');
 $datetime1 = date_create('2009-10-11');
 $datetime2 = date_create('2009-10-13');
 $interval = date_diff($datetime1, $datetime2);
-echo $interval->format('%R%d days');
+echo $interval->format('%R%a days');
 ?>
 ]]>
    </programlisting>