diff --git a/public/js/customizeRoom.js b/public/js/customizeRoom.js
index fcbee592..b6c8c625 100644
--- a/public/js/customizeRoom.js
+++ b/public/js/customizeRoom.js
@@ -62,7 +62,7 @@ document.addEventListener('DOMContentLoaded', () => {
         // Accept HH:MM:SS format only
         const re = /^(\d{2}):(\d{2}):(\d{2})$/;
         if (!re.test(value)) {
-            throw new Error('Duration must be HH:MM:SS (e.g. 12:30:00) or left empty for unlimited');
+            throw new Error('Duration must be HH:MM:SS (e.g. 00:30:00) or left empty for unlimited');
         }
         return value;
     };
diff --git a/public/views/customizeRoom.html b/public/views/customizeRoom.html
index 0451146d..e8312563 100644
--- a/public/views/customizeRoom.html
+++ b/public/views/customizeRoom.html
@@ -144,7 +144,7 @@
                             class="cr-input"
                             type="text"
                             inputmode="numeric"
-                            placeholder="12:30:00"
+                            placeholder="00:30:00"
                             pattern="^\d{2}:\d{2}:\d{2}$"
                             maxlength="8"
                         />