diff --git a/games/static/js/utils.js b/games/static/js/utils.js
index 988e0a7..5b51cc5 100644
--- a/games/static/js/utils.js
+++ b/games/static/js/utils.js
@@ -5,5 +5,6 @@
  */
 export function toISOUTCString(date) {
   let month = (date.getMonth() + 1).toString().padStart(2, 0);
-  return `${date.getFullYear()}-${month}-${date.getDate()}T${date.getHours()}:${date.getMinutes()}`;
+  let day = date.getDate().padStart(2, 0);
+  return `${date.getFullYear()}-${month}-${day}T${date.getHours()}:${date.getMinutes()}`;
 }