diff --git a/theme/theme.inc b/theme/theme.inc
index 82fb5fb..f878041 100644
--- a/theme/theme.inc
+++ b/theme/theme.inc
@@ -283,7 +283,24 @@ function template_preprocess_calendar_day(&$vars) {
           if (!empty($group_time) && !empty($divisor)) {
             $start_minute = intval(substr($start_time, 3, 2));
             $offset = round((date_format($item->date_start, 'i') - $start_minute) / $divisor);
-            $duration = round(($item->date_end->format('U') - $item->date_start->format('U')) / 60 / $divisor);
+
+            // Get the start and end datetime of the calendar view
+            $calendar_start_date = new DateTime($view->date_info->date_range[0]->originalTime);
+            $calendar_end_date = new DateTime($view->date_info->date_range[1]->originalTime);
+            
+            // Save the start and end date of the node in two working variables
+            $event_start = $item->date_start;
+            $event_end = $item->date_end;
+            
+            // Put the time to the limits (00:00:00 and 23:59:59) if the event is not in the actual day
+            if (date_format($event_start, 'd') < date_format($calendar_start_date, 'd')) {
+              $event_start = $calendar_start_date;
+            }
+            if (date_format($event_end, 'd') > date_format($calendar_end_date, 'd')) {
+              $event_end = $calendar_end_date;
+            }
+            
+            $duration = round(($event_end->format('U') - $event_start->format('U')) / 60 / $divisor);
             $item->class = 'd_' . $duration . ' o_' . $offset . ' i_' . $item->indent . ' md_' . min($item->max_depth, 5);
           }
         }