How do I update events without duplicating everything in Google calendar??

Useless unless you buy it. Don't waste your time.

cant make an event multiple days, when I put in nb days it defaults it to 1.

This did exactly what I was looking for. Had a list of 30 days of workouts. I just added the list to google sheets, and created the calendar events using this add-on. Only thing I had to do then was go into the calendar settings and add a reminder to be applied to all events. Thank you!

Basic functionality is there to populate a calendar, but when you do the first thing that pops up in the description is a link to the creator's website so it was unusable for me. Would this have gone away if I donated? No idea, but if I knew maybe I could have done that. Removing items from my spreadsheet also did not remove items from the calendar so it seems that if I were to make 100 calendar events, and need to modify them all I would need to manually do so.

OK, easy enough to use, it would be really useful if there was an option to automatically refresh the calendars after they have been uploaded

This sucks. Been trying for half an hour, all I get is "No events will be added to your calendar" without any indication of what's wrong. Hence, two stars Review Update: FastCalendar uses a number of hidden columns and if you inadvertently change those, the item is skipped without clear message ("No events...") In addition, the buttons "Create All ..." don't give clear feedback when you press them. When you press them multiple times, multiple copies of entries will result. But to be fair I've updated the rating to 4 star

Does exactly what it says on the tin and has streamlined front office processes at our school. Prompt and efficient support provided by David. Highly recommended.