diff --git a/calendar/event.php b/calendar/event.php
index 3a975da24ef..945aa5a70d2 100644
--- a/calendar/event.php
+++ b/calendar/event.php
@@ -554,14 +554,14 @@ list($nextmon, $nextyr) = calendar_add_month($mon, $yr);
 
 echo '<td class="sidecalendar">';
 echo '<div class="sideblock">';
-echo '<div class="header">'.get_string('eventskey', 'calendar').'</div>';
+echo '<div class="header"><h2>'.get_string('eventskey', 'calendar').'</h2></div>';
 echo '<div class="filters">';
 echo calendar_filter_controls('event', 'action='.$action.'&amp;type='.$eventtype.'&amp;id='.$eventid);
 echo '</div>';
 echo '</div>';
 
 echo '<div class="sideblock">';
-echo '<div class="header">'.get_string('monthlyview', 'calendar').'</div>';
+echo '<div class="header"><h2>'.get_string('monthlyview', 'calendar').'</h2></div>';
 echo '<div class="minicalendarblock minicalendartop">';
 echo calendar_top_controls('display', array('id' => $urlcourse, 'm' => $prevmon, 'y' => $prevyr));
 echo calendar_get_mini($courses, $groups, $users, $prevmon, $prevyr);
@@ -660,4 +660,4 @@ function calendar_add_event_allowed($event) {
     }
 }
 
-?>
\ No newline at end of file
+?>