Google's built-in way is to share a calendar from account A to account B. In A's Google Calendar, open the calendar's Settings and sharing, share it with B, and choose See only free/busy (hide details) or See event details. B adds it from the invite email, and it shows as another calendar overlaid on B's view.
That overlay is a view, not a block. Sharing does not write A's events onto B's own calendar. Other people booking B, and B's appointment-schedule booking page, do not automatically treat A's events as B's busy time unless B's owner sets those extra calendars to be checked. If the calendar is for work or school, an administrator may restrict sharing outside the organization.
You can also copy a calendar's secret address in iCal format and add it on the other account with Add by URL. Google Calendar Help does not publish a refresh interval you can set for URL subscriptions. People commonly report that those feeds update after hours, not minutes.
Resync is a different tool: it reads busy time from Google calendars you mark as sources and writes hold events titled Busy onto Google calendars you mark as mirrors.
Built-in option: share the calendar
To overlay account A's calendar on account B, share it with that other Google account:
- In account A, open Google Calendar. Next to the calendar, open Settings and sharing.
- Under Shared with, add account B's email.
- Choose See only free/busy (hide details) if B should only see when you are busy, or See event details if B should see names, times, places, and descriptions.
- Send the invite. B opens the email and adds the calendar. It appears under Other calendars.
Google Calendar Help steps checked Oct 31, 2026.
What sharing does not do
- It is a view. A's events stay on A's calendar. They do not become events on B's calendar.
- Other people booking B do not automatically see A's busy time. B's booking page only checks extra calendars if B's owner turns that on and selects them. Checking secondary calendars needs an eligible Workspace or Google One plan.
- Work or school admins can limit or block external sharing. Google Calendar Help also says your administrator decides whether you can share a work or school calendar.
Secret iCal address and Add by URL
Another built-in path is to copy the secret address in iCal format from Integrate calendar, then add that URL under Other calendars on the second account. Google says the secret address is meant for viewing that calendar in another app, including the events on it, and that you should not share it with other people. Admins can hide it. Google Calendar Help does not publish a refresh interval you can set. People commonly report that URL subscriptions update after hours, not minutes.
How Resync's Busy holds work
Resync does not share calendars with each other. It reads when you are busy on Google calendars you mark as sources and writes hold events onto Google calendars you mark as mirrors.
- Holds are titled Busy. Description, location, attendees, and conference data are left empty, so source meeting details stay on the source calendar.
- When you mark calendars as both source and mirror, a booking on either calendar becomes a Busy hold on the others. That is two-way blocking between those Google calendars.
- If a source event moves, Resync updates the hold. If the event is cancelled, marked free, declined, or is a working-location event, Resync does not keep a hold.
- Resync looks 90 days ahead when it reads source events. Holds it writes are marked so they are not copied again.
- If you delete or edit a hold, Resync records that and does not recreate it for the same source event on that mirror.
- Read-only calendars cannot be mirrors. Resync currently syncs Google calendars only.
Use sharing when you only need to see the other calendar. Use Resync when the calendars that get booked should treat the other account's busy time as busy — for example a personal Gmail calendar and a work Google Calendar.
Set up Resync
- Sign in with GoogleOpen Resync and sign in with the Google account you want as your primary account. You land on setup.
- Connect another Google accountChoose Connect another Google account and finish Google's permission screen. Resync needs at least two Google accounts before you can start.
- Start syncingWhen a second account is connected, setup shows bidirectional mirroring as the intended default: real events on either side become private busy blocks on the other. Choose Start syncing to open the dashboard.
- Mark sources and mirrorsIn Sync configuration, turn on Source to read busy time from a calendar and Mirror to receive Busy holds. A calendar can be both. Read-only calendars cannot be mirrors because Resync needs write access to create holds.
Compare the options
| Compare | Share calendar | iCal URL subscription | Resync |
|---|
| Blocks your time for others | No, not by itself. The shared calendar is an overlay under Other calendars. Booking pages only check it if that account's owner turns on extra-calendar availability and selects it. | No, not by itself. A URL subscription also lands under Other calendars. Same booking-page caveat as sharing. | Yes. Resync writes Busy holds onto the mirror calendar, so they are events on that calendar. |
|---|
| Shows event details | Only if you grant See event details. See only free/busy (hide details) hides names and other details. | The secret iCal address is meant to show that calendar, including its events. A public address can be limited to free/busy. | No. Holds are titled Busy. Description, location, attendees, and conference data stay empty. |
|---|
| Update speed | The other account sees it in Google Calendar after they add it from the share email. This is Calendar sharing, not a polled URL. | Google does not publish a refresh interval you can set. People commonly report that URL subscriptions update after hours, not minutes. | Resync watches source calendars and updates or removes holds when those events change, move, or are cancelled. |
|---|
| Works across Workspace orgs | Maybe. A work or school admin decides whether you can share, and can limit what people outside the organization see. | Maybe. Admins can hide the secret iCal address and restrict public sharing. | If you can sign in to both Google accounts and grant calendar access, Resync can read one and write holds on the other. It does not depend on sharing the calendars with each other. |
|---|
Share calendar
- Blocks your time for others
- No, not by itself. The shared calendar is an overlay under Other calendars. Booking pages only check it if that account's owner turns on extra-calendar availability and selects it.
- Shows event details
- Only if you grant See event details. See only free/busy (hide details) hides names and other details.
- Update speed
- The other account sees it in Google Calendar after they add it from the share email. This is Calendar sharing, not a polled URL.
- Works across Workspace orgs
- Maybe. A work or school admin decides whether you can share, and can limit what people outside the organization see.
iCal URL subscription
- Blocks your time for others
- No, not by itself. A URL subscription also lands under Other calendars. Same booking-page caveat as sharing.
- Shows event details
- The secret iCal address is meant to show that calendar, including its events. A public address can be limited to free/busy.
- Update speed
- Google does not publish a refresh interval you can set. People commonly report that URL subscriptions update after hours, not minutes.
- Works across Workspace orgs
- Maybe. Admins can hide the secret iCal address and restrict public sharing.
Resync
- Blocks your time for others
- Yes. Resync writes Busy holds onto the mirror calendar, so they are events on that calendar.
- Shows event details
- No. Holds are titled Busy. Description, location, attendees, and conference data stay empty.
- Update speed
- Resync watches source calendars and updates or removes holds when those events change, move, or are cancelled.
- Works across Workspace orgs
- If you can sign in to both Google accounts and grant calendar access, Resync can read one and write holds on the other. It does not depend on sharing the calendars with each other.
FAQ
Does sharing a Google Calendar block time on the other account?
No. Sharing lets the other account overlay that calendar under Other calendars. It does not write those events onto B's own calendar. Appointment-schedule booking pages only check extra calendars if B's owner turns that on and selects them, and checking secondary calendars needs an eligible Workspace or Google One plan.
Can I merge two Google Calendars into one?
Not with sharing, a URL subscription, or Resync. Sharing and URL subscriptions add an overlay. Resync writes Busy holds onto the calendars you mark as mirrors. None of these copy event titles into a single merged calendar.
How do I sync a work and personal Google Calendar?
Connect both Google accounts in Resync, choose Start syncing, then in Sync configuration mark each calendar as a Source, a Mirror, or both. A calendar can be both so a booking on either side becomes a Busy hold on the other. Read-only calendars cannot be mirrors.
Does Resync copy event titles or attendees?
No. The hold is titled Busy. Description, location, attendees, and conference data are left empty. Free, declined, and working-location source events do not get a hold. Resync also skips holds it already wrote, so those Busy events are not copied back.
What if I delete or edit a Busy hold that Resync created?
Resync records that change and does not recreate a hold for the same source event on that mirror calendar.
How far ahead does Resync sync?
Resync reads source events in a 90-day window from now. If a source event moves, Resync updates the hold. If the event is cancelled, marked free, or declined, Resync removes the hold.
Connect the Google calendars you want to keep aligned, then mark sources and mirrors on the dashboard.
Resync will ask Google for permission to:see your list of calendars; see events on the calendars you choose as Sources, to know when you're busy; and create, update and delete events titled "Busy" on calendars you choose as Mirrors. We never store event titles, attendees or locations. Privacy policy
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