diff --git a/defaultmodules/calendar/calendarutils.js b/defaultmodules/calendar/calendarutils.js
index 9b43de8503..9349c0666e 100644
--- a/defaultmodules/calendar/calendarutils.js
+++ b/defaultmodules/calendar/calendarutils.js
@@ -109,7 +109,7 @@ const CalendarUtils = {
 					let replacement = transform.replace;
 					if (typeof transform.yearmatchgroup !== "undefined" && transform.yearmatchgroup !== "") {
 						const yearmatch = [...title.matchAll(needle)];
-						if (yearmatch[0].length >= transform.yearmatchgroup + 1 && yearmatch[0][transform.yearmatchgroup] * 1 >= 1900) {
+						if (yearmatch.length > 0 && yearmatch[0].length >= transform.yearmatchgroup + 1 && yearmatch[0][transform.yearmatchgroup] * 1 >= 1900) {
 							let calcage = new Date().getFullYear() - yearmatch[0][transform.yearmatchgroup] * 1;
 							let searchstr = `$${transform.yearmatchgroup}`;
 							replacement = replacement.replace(searchstr, calcage);