WordPress guide
Add a Christmas Countdown to WordPress
WordPress accepts the MerryMeter iframe in a standard Custom HTML block. You do not need a plugin, API key or theme edit.
Build your widget
Choose the theme, units and size on the MerryMeter widget page, then copy the generated embed code.
Add a Custom HTML block
Open the post or page editor, select the + inserter and search for “Custom HTML”.
Paste and preview
Paste the iframe, switch to Preview, then publish or update the page when the size looks right.