How to add WebCal/iCalendar to Google Calendar by a direct link

Question

You can add a calendar hosted on Google to your Google Calendar account by a direct link (for example as on Holidays in Australia - the button in the bottom left corner - if you click on it, the calendar will be added to your account).
I have a webcal calendar on my site and I want to add a button like in the example which points to my calendar.
How can I do that?

Answer 1

You can do this with this link:

https://www.google.com/calendar/render?cid=

With after the = symbol the link to your ICS file. For example:

https://www.google.com/calendar/render?cid=http://www.example.com/calendar.ics