Like a lot of people, I don’t live in one calendar. Work is on one, personal on another, side projects on a third. And the problem with that is simple: the people looking at one of my calendars can’t see that I’m busy on the others. So they book me. Over dinner. Over a meeting. Over the one hour I’d blocked to actually get something done.
All I wanted was a way to block that busy time across my calendars — so that when I’m busy anywhere, I look busy everywhere. Not a scheduling suite. Not a productivity platform. Just: keep my calendars honest with each other.
The tools we tried did too much — and the core thing worked badly
Every option I looked at was overloaded. Meeting polls, booking widgets, analytics dashboards, integrations with things I’ll never use. And here’s the part that really decided it: when I tested them, the basics didn’t hold up. The one thing I cared about most — syncing a calendar both ways — either didn’t work, silently dropped events, or created duplicates and loops. The flagship feature list was a mile long, but the fundamental job was unreliable.
So we built Calendar-Sync
- Block your busy time everywhere. Connect two calendars, make one rule, and your events mirror across as clean “busy” blocks — no private details leak.
- One way or both ways — and bidirectional actually works. Create an event on either calendar and it appears on the other, with real loop protection and no duplicates.
- It just runs. Set the rule once; it syncs quietly in the background. Nothing to babysit.
- Your data stays yours. Self-hosted, encrypted, no third party mining your schedule.
A nice bonus: free booking availability across all your calendars
Google’s “Appointment Scheduling” — the book-time-with-me page — only checks your primary calendar for conflicts. So people can book you when you’re busy elsewhere, unless you upgrade to Business Standard. Because Calendar-Sync mirrors your other calendars’ busy-times into your primary, your booking page suddenly respects all of them. No upgrade required. (One-time step: tick your calendar under “Calendars checked for availability” in your Appointment Scheduling settings.)
The point
We built Calendar-Sync because we needed it and couldn’t find a version that was both simple and reliable. If your life is spread across a few calendars and you just want them to stop letting people double-book you — this is the tool that does that one thing, and does it well.