diff --git a/main.js b/main.js
index 38d565c..5e1692b 100644
--- a/main.js
+++ b/main.js
@@ -355,15 +355,15 @@ class CalendarView extends ItemView
 
 	gotoPreviusWeek()
 	{
-		let date = this.week.match(/y([0-9]{2})w([0-9]{2})/);
-		this.week = "y" + date[1] + "w" + (parseInt(date[2]) - 1).toString();
+		let date = parseSingleDate(this.week + ' ma 12:00am', null).subtract(7, 'days');
+		this.week = stringifySingleDate(date).match(DateFormat.week)[0];
 		this.updateWeek();
 	}
 
 	gotoNextWeek()
 	{
-		let date = this.week.match(/y([0-9]{2})w([0-9]{2})/);
-		this.week = "y" + date[1] + "w" + (parseInt(date[2]) + 1).toString();
+		let date = parseSingleDate(this.week + ' ma 12:00am', null).add(7, 'days');
+		this.week = stringifySingleDate(date).match(DateFormat.week)[0];
 		this.updateWeek();
 	}