diff --git a/apps/calendar/calendar.js b/apps/calendar/calendar.js
index da5a00a6e..ea06b70e8 100644
--- a/apps/calendar/calendar.js
+++ b/apps/calendar/calendar.js
@@ -227,8 +227,8 @@ const drawCalendar = function(date) {
   }, []);
   let i = 0;
   g.setFont("8x12", fontSize);
-  for (y = 0; y < rowN - 1; y++) {
-    for (x = 0; x < colN; x++) {
+  for (let y = 0; y < rowN - 1; y++) {
+    for (let x = 0; x < colN; x++) {
       i++;
       const day = days[i];
       const curMonth = day < 15 ? month+1 : day < 50 ? month-1 : month;