Calendar sync and double booking
Check all your calendars to prevent double booking
Connect each calendar account you use: one Google, one Microsoft 365 and one iCloud account. Caletus hides the times you're busy on any of them, so nobody can book over another commitment.
- Works on
- All plans (Free, Professional, Enterprise)
- Length
- 5 steps · about 2 min
- Last reviewed
- October 14, 2026
What you need to check several calendars for conflicts
- Your main calendar already connected (see Connect Google Calendar or Outlook to Caletus)
- The sign-ins for your other calendar accounts
- For iCloud, your Apple ID and two-factor authentication turned on, so you can create an app-specific password
How to check several calendars for conflicts
Tick each one off as you go.0 of 5 done
Open the Calendars list
In the Caletus sidebar, click Integrations and find the Calendars group.IntegrationsCalendarsConnect your other accounts
Click Connect on Google Calendar, Office 365 Calendar or Apple Calendar for each account you haven't added yet. Each person can connect one account of each kind.CalendarsConnectConnect iCloud with an app-specific password
Apple Calendar asks for your Apple ID email and an app-specific password. Create one at appleid.apple.com under Sign-In and Security > App-Specific Passwords, then paste it in.Apple CalendarApple ID email and app-specific passwordChoose which calendars block your time
For iCloud, tick the calendars under 'Check these calendars for conflicts' and, if you like, pick one under 'Add new bookings to'. For Google and Outlook, click Configure on the card to see the calendars Caletus checks.Apple CalendarCheck these calendars for conflictsInclude calendars you never book from, like a family calendar. They only need to block time.Test it with a busy event
Add a test event to one of your other calendars, set it to 'Busy', and check that the time is gone from your booking page. iCloud changes can take about a minute to show. Delete the test event afterwards.
How you'll know it worked
All your calendars are checked
A time that's busy on any connected calendar doesn't appear on your booking page. Google and Outlook are checked again when a guest confirms, so if the time was just taken, the guest is asked to pick another.Look forGreen 'Connected' badge on each calendar card
Fixes for common double booking problems
If it doesn't work, find what you're seeing below.- Likely causeThe event is probably marked 'Free' or 'Tentative' instead of 'Busy'.FixOpen the event in Google Calendar, Outlook or Apple Calendar and set it to show as 'Busy'.
- Likely causeCaletus connects one Google, one Microsoft 365 and one iCloud account per person.FixShare the other calendar into an account you've already connected (for example, subscribe to it in Google Calendar), so Caletus can check it there.
- Likely causeCaletus refreshes iCloud busy times about once a minute.FixWait a minute, then reload your booking page.
- Likely causeCaletus was signed out of that account, usually after a password change. For iCloud, the app-specific password may have been revoked.FixOn the Integrations page, disconnect that calendar and connect it again. For iCloud, create a new app-specific password.