Your event page shows your description exactly as you format it. Calendar apps are less consistent, so this article covers what the editor supports and how each kind of calendar shows it.
What the editor supports
The description uses a rich-text editor with a toolbar. Press Enter to start a new paragraph. Typing HTML tags such as <br> into the editor does not work; they show as plain text.
Free plan: bold, italic, underline, two heading sizes, bullet and numbered lists, quotes and links.
Premium and Business: everything above, plus strikethrough, a smaller heading size, text alignment, images, tables and code blocks.
If a heading lost its alignment before 26 August 2026, select it, set the alignment again and click Update Event.
How calendar apps show your description
AddCal sends both a formatted and a plain-text version of your description. Each calendar app decides which one to show, so check the event in the app your audience uses most.
Google Calendar receives the formatted version.
Outlook often shows the plain-text version, so tables and styling may be lost. They are still kept on your AddCal event page.
Apple Calendar, Yahoo and most other apps show the plain-text version. In it, each linked word becomes a numbered note, for example "Register [1]", with the full web address listed at the end of the description. Links where the text is the web address itself are left as they are.
For a description that looks the same everywhere, use short paragraphs, lists and links, and avoid tables.
Long descriptions in add-to-calendar buttons
Add-to-calendar buttons that open Google Calendar or Outlook on the web shorten descriptions longer than about 1,000 characters. The rest is replaced with a "View full details at" link to your event page.
Pasting the Add to Calendar Links block into Outlook
Classic Outlook for desktop pastes the block like a Word document and can break the buttons. Paste it into the new Outlook, or into Outlook on the web, instead.
Creating events through the API
If you create events through the API, the description field accepts basic HTML. See Developer API and Dynamic Links.