diff --git a/calendar/js/app.js b/calendar/js/app.js
index 555ed6f8b6..8476053d2d 100644
--- a/calendar/js/app.js
+++ b/calendar/js/app.js
@@ -3426,6 +3426,7 @@ app.classes.calendar = AppJS.extend(
 		 */
 		granularity: function(state) {
 			var list = egw.preference('use_time_grid','calendar');
+			if(list === 0) return parseInt(egw.preference('interval','calendar')) || 30;
 			if(typeof list == 'string') list = list.split(',');
 			if(!list.indexOf && jQuery.isPlainObject(list))
 			{