Calendar Sync mirrors events between your calendars and rewrites the title to "Busy" on the way over. Free, no signup to try it.

If you have a work calendar on Google and a personal one on Outlook (or any combo), they don't know about each other. Coworker books you 4 PM Monday, you accept, now you're double-booked with a therapist appointment that lives elsewhere. The fix nobody bothers with is the one that works: a one-way sync that mirrors your busy time without leaking details. Calendar Sync does that.

What it does

Pick a source calendar (real titles) and a destination (the one coworkers see). Calendar Sync watches the source for new, updated, or deleted events and copies them over. Source is never modified.

The interesting part is the rule layer. Before each event copies, you decide what to keep and what to strip:

• Title — keep, replace with "Busy," or use a template like [Personal] {original_title}.
• Description, Location, Attendees — keep, blank, or override.
• Show as — Busy, Free, or Tentative regardless of how the source is marked.

Conditions are arbitrary: visibility, attendee count, day of week, duration, organizer email, location, all-day vs. timed. "If visibility = private, copy as 'Busy' with attendees stripped" — everything else mirrors through unchanged.

Four presets cover most cases

1. Mask private events as "Busy" — private events become featureless blocks; default events copy as-is.
2. Mask everything as "Busy" — maximum privacy.
3. Strip attendees only — keep titles, don't leak the guest list.
4. Show copies as Free — destination knows the events exist but doesn't treat them as conflicts.

Pick one in the tool and you're done.

Why not just share a calendar

Native sharing is all-or-nothing. Either coworkers see everything or they don't. Free/busy permissions exist but leak edge cases nobody trusts. A separate sync layer flips the model: produce a sanitized copy on the calendar people already have access to. They see one calendar — the work one — and it's already accurate.

Calendar Sync is free and runs alongside the rest of Carly's free tools — group polls, booking pages, and the MCP server. No paid account required.

Try Calendar Sync →