Simple Calendar is an extensible plugin that supports add-ons, which are simply WordPress plugins themselves that add features and functionalities to the core plugin. See our complete list of add-ons.

When installing an add-on plugin you must ensure that Simple Calendar is already installed and activated.

Premium Add-on Step-by-Step Instructions

  1. From your purchase email, click the download link(s) and save the add-on zip file(s) to your computer (,, etc.).
  2. Log in to your site’s WordPress admin (e.g.
  3. Click on the “Plugins” tab in the left panel, then click “Add New”.
  4. Click the Upload link near the top, then “Choose File”.
  5. Find and select one of the add-on zip files that you downloaded.
  6. Install it by clicking the “Install Now” link.
  7. When installation finishes, click “Activate Plugin”.
  8. Repeat the above steps for any additional premium add-ons your purchased and downloaded.
  9. Enter your add-on license key(s) (instructions below).

Note for Safari users: If when clicking the download link a folder is saved instead of a zip file, try Control-click or right-click and select “Download Linked File”. Plugins must be in a zip file format before uploading to your WordPress site.

Premium Add-on License Key Activation

To receive automatic updates and premium support, you need to activate your premium add-on license key(s).

  1. From your purchase email, copy one of your license keys.
  2. From your site’s WordPress admin, click on the “Calendars > Settings” menu item in the left panel, then click “Add-on Licenses”.
  3. Paste in the license key, then “Activate”.
  4. Repeat for additional premium add-ons purchased and installed.

If you’re setting up the Google Calendar Pro add-on, next you’ll need to configure a Google OAuth client.