Important: This concept of using calculated columns will only work as a one-time trick. After adding the column, links will be correct. But because [ID] isn’t meant to be used in calculated columns, it removes itself from the formula if an item is edited after the column has been added. This method is only ideal for one-time uses, or for lists that are not expected to have content additions or changes. See this other post about how to get the same hyperlinks through workflow instead, for a more reliable method.
This project allows users a quick option to save something they see on a SharePoint calendar to their own calendar. Spend 5 minutes on these few instructions and your users will have a convenient way to get involved going forward.
Note that in modern calendar experiences, there’s a built-in “add to calendar” option for event items. This post is for classic experience calendars and calendar items/events.
Basically we’re going to add a calculated text column called iCal which will use the list’s GUID (easy to get, don’t worry) and the specific calendar item’s default ID number to generate a clickable .ics (iCal) file link. Let’s get started!