SP countdown is a lightweight countdown module and suitable for Events. You can choose the year, month, day, hour, minute and even the second at which your event begins. It can be used as a standalone module in any module position or inside SP Page Builder structure, remember to use module addon for it.
Note! This module request mootools-core.js file to make it work, which should be loaded from Joomla! core resources. Mentioned file you will find here: media/system/js.