A booking tool such as Calendly offers a time slot unless one of the calendars connected to it shows that time as busy, so an event on any other calendar leaves the slot open. Keeper.sh is a calendar sync service that copies events between Google Calendar, Outlook, iCloud, Fastmail and any CalDAV server, so every calendar shows you as busy at the same times. It is free for 2 calendar accounts and 3 connections, and Pro is $5 a month for unlimited calendars.
Which calendars Calendly can check
Calendly connects three kinds of calendar: Google Calendar, Office 365 or Outlook.com, and Exchange. Its free plan connects 1 calendar and its paid plans connect up to six per user (Calendly's guide to connecting a calendar, checked 10 November 2026). Once connected, Calendly checks that calendar for busy times, and it adds each new meeting to one calendar you choose. Calendly stopped accepting new iCloud Calendar connections on 20 August 2024, and connections made before that date keep working (Calendly's platform security and compliance page, checked 10 November 2026). How to stop Calendly double-booking lists each calendar Calendly cannot check and what closes each gap.
One checked calendar, with every other calendar copied onto it
Every connection points at the calendar your booking tool checks.
- Personal iCloud to work Google. Calendly checks the work Google calendar. One connection copies iCloud events onto it. That is 2 calendar accounts and 1 connection.
- Bookings back to the personal calendar. Calendly writes new meetings to the calendar you chose in Calendly. A second connection, work Google to personal iCloud, shows those bookings at home. That is 2 accounts and 2 connections.
- A third calendar. A client mailbox or a second job is a third calendar account, which needs Pro. Its connection also points at the checked calendar.
Each copy is a busy block named after the source calendar. The title, description and location are hidden by default, Pro can turn them back on per calendar, and guest lists are never copied. A booking tool reads only whether the time is busy, so the people booking you see a slot that is missing from the page and nothing else. If the checked calendar is one your employer can read, a personal appointment appears there as a block titled with the personal calendar's name.
Set up Keeper.sh for a Calendly booking page
- Create a Keeper.sh account with an email address and a password.
- Connect the calendar Calendly checks: choose Google Calendar or Outlook or Microsoft 365 and sign in on Google's or Microsoft's own screen.
- Connect the calendar Calendly cannot see. iCloud asks for an app-specific password from your Apple account settings. Fastmail and CalDAV are under Fastmail, CalDAV or a calendar link, where Connect Fastmail asks for an app password and Connect a CalDAV server for the server address and sign-in details.
- On the Ready to sync screen, keep the direction that copies the unseen calendar onto the checked one. Keep the other direction on if Calendly bookings should also show on the second calendar. Choose Start syncing.
- In Calendly, leave the checked calendar connected and selected for conflict checking, as before.
Nothing is installed in Calendly and Keeper.sh does not connect to it. To add a calendar later, choose Add a calendar on the Keeper.sh dashboard, open the new calendar and tick the checked calendar under Send Events to Calendars.
How fast a new event closes the slot
Events that already exist when you create the connection are copied straight away on either plan. A new event's slot stays bookable until its copy lands on the checked calendar. On Pro, Google and Outlook changes land within seconds, and iCloud, Fastmail and CalDAV changes land every minute. On Free, changes land every 30 minutes.
When an event is cancelled or moved, Keeper.sh deletes or moves the copy, so the booking tool finds that time free again.
Other booking tools
The same layout works with any booking tool that reads a Google Calendar, Outlook, iCloud, Fastmail or CalDAV calendar for conflicts. A Keeper.sh copy is an ordinary event on that calendar, so the booking tool treats it like any meeting you created by hand.
What it costs
Free covers 2 calendar accounts and 3 connections. Pro is $5 a month or $45 a year for unlimited calendars (pricing). The checked calendar and one other calendar, with a connection in each direction, use 2 accounts and 2 connections.
Pro adds a third and further calendar accounts, faster updates, and the choice of which events count: all-day events, focus time and out-of-office blocks can each be left out of the copy, so a birthday reminder does not close a whole day of slots. The calendar sync features page lists the rest.
Common questions about Calendly and Keeper.sh
Does Keeper.sh work with Calendly?
Yes. Keeper.sh writes busy blocks onto the Google Calendar or Outlook calendar that Calendly checks for conflicts, and Calendly reads them like any other event. Nothing changes in Calendly's settings.
Can Calendly block time from an iCloud calendar?
Yes, through a copy. Calendly has not accepted new iCloud connections since 20 August 2024, so Keeper.sh copies iCloud events onto a Google Calendar or Outlook calendar that Calendly checks. On Pro, iCloud changes land every minute.
Is Keeper.sh free for one Calendly calendar and one other calendar?
Yes. Keeper.sh's Free plan covers 2 calendar accounts and 3 connections, and this setup uses 2 accounts and 1 connection, or 2 connections if bookings are copied back.
Do I need a paid Calendly plan to check more than one calendar?
No. Keeper.sh puts the busy time from your other calendars onto the one calendar Calendly's free plan connects, so Calendly only has to check that one.
Do Calendly bookings appear on my other calendars?
Yes, with a second connection. Keeper.sh copies events one way per connection, so a connection from the calendar Calendly writes to into your other calendar shows each booking there as a busy block.