Quick answer: If you only need to see two Google calendars together, try Google's native sharing first. If appointments must be copied into the calendar your colleagues or booking tool checks, compare a sync tool. SYNCDATE, Reclaim, OGCS, Keeper and SyncGene offer free options, with different limits and operating requirements.
For one permitted two-calendar arrangement, SYNCDATE Free supports one-way or two-way copying, no card required. Start with the setup below and verify both the copied fields and actual availability. We make SYNCDATE; this is our assessment of fit, not a comparative performance test.
Choose by the result you need
| Your job | Start here | Check before connecting |
|---|---|---|
| See both Google calendars on one screen | Native Google sharing | Sharing permission and which details the other account can see |
| Put private personal commitments in a work calendar | Personal-to-work Busy setup | Work write permission, copied fields and Free/Busy |
| Copy original events in both directions | Multiple-calendar setup guide | Both calendars must be writable; review appearance before starting |
| Add calendar copying to an existing scheduling service | Reclaim's free plan | Its Calendar Sync allowance and supported account arrangement |
| Run Google–Outlook sync from a Windows computer | OGCS | Classic Outlook versus the v3 Outlook Online connection |
| Use a hosted or self-managed open-source tool | Keeper | Hosted Free limits versus self-hosting responsibilities |
| Reconcile occasionally by hand | SyncGene Free | Monthly manual allowance; automatic sync is a trial |
The five tools below were checked against their own pages on October 28, 2026. We did not test their comparative speed or every account configuration.
How we picked these tools
A permanent free allowance qualifies for this list. A trial alone does not. SyncGene qualifies for its monthly manual allowance, although ongoing automatic sync requires payment.
The best choice depends on your calendar providers, permissions and need for copies. We make SYNCDATE. This list explains fit and published limits; it does not rank products by a comparative performance test.
The linked vendor pages supply the plan and compatibility details below. We do not assign a speed to a tool unless its vendor publishes one. Hosted services, desktop applications and self-hosted software also have different operating requirements.
Native sharing may already solve the problem
Google lets you share a calendar with another account and choose its access level, including free/busy only or event details. Work and school administrators can restrict sharing. Follow Google's sharing instructions.
Sharing can work across Google accounts. It grants access to the existing calendar rather than automatically making independent copies in the recipient's primary calendar. If your booking tool can check that shared calendar, a separate sync may be unnecessary. Confirm which calendars it actually checks before paying for a copying service.
An ICS import is a one-time transfer; a subscription is a separate read-only calendar with its own refresh behavior. Neither should be assumed to create private Busy copies in a work mailbox. Sharing versus syncing explains the distinction.
1. SYNCDATE — one hosted two-calendar arrangement
Free covers 2 accounts, 2 calendars and 1 sync, with a 30-day forward window. Choose a one-way Push when personal commitments should reach work without sending work events back; choose a two-way Mirror when originals from either calendar should travel to the other. Separate syncs do not relay their copied events onward.
New syncs copy events as Busy. A two-way Mirror between calendars you own keeps the real titles. You can change either before you start. Check Description, Location, Guests, Privacy and Free or busy independently: a Busy title alone does not make an event unavailable.
Google and Outlook changes usually reach the other calendar in under a minute. CalDAV and iCal are polled about every 15 minutes on all plans. Google/Outlook fallback polling is separate: paid plans use 15 minutes; Free uses two hours while the push channel is healthy, or one hour without a live push channel. Provider limits, missed notifications and retries can add delay.
Use the Free plan explanation for the starting allowance and current pricing for larger requirements. A third account, a longer forward window or different appearance per destination can require a paid plan. No plan bypasses company connection restrictions.
Set up a personal-to-work copy
- Confirm that you may connect both accounts and that the work calendar is writable.
- Review the personal-to-work recipe. Its button opens the builder; you still select the calendars and review the settings.
- Choose personal as the source and work as the destination. Keep the title Busy and omit private descriptions, locations and guests.
- Review Free or busy. Same as original can preserve a Free source event; Always busy is the choice when every eligible copy must block time.
- Before relying on the arrangement, complete the harmless verification below.
If you need real titles in one destination and masked copies in another within the same sync, check appearance settings and the current paid requirement first.
2. Reclaim — calendar copying alongside scheduling
Reclaim's pricing page lists a permanent free plan with one Calendar Sync. Its plan guide calls the free tier Lite. Check the current allowance rather than treating every feature shown during a trial as free forever.
This is worth comparing if you also want Reclaim's time-blocking and scheduling features. Calendar copying and automatic task scheduling are different jobs; decide whether you need both. Confirm the calendar combination and privacy behavior in Reclaim's own setup instructions before connecting.
See the Reclaim alternative comparison if calendar copying is your main reason to compare plans.
3. OGCS — Google–Outlook copying on Windows
Outlook Google Calendar Sync is free and open source, with one-way and two-way Google–Outlook synchronization. It runs as a Windows application, so consider the computer that will run it and the permissions your employer allows.
Its current site distinguishes versions: v2 requires Classic Outlook; the v3 alpha offers an Outlook Online connection for Microsoft 365 and new Outlook users. The older blanket claim that every version requires installed Classic Outlook is no longer accurate. Choose the supported version deliberately, especially for a work calendar. This is a Google–Outlook option, rather than a tool for copying directly between two Google accounts.
4. Keeper — hosted Free or self-hosted
Keeper's current site lists hosted Free with up to two linked accounts, three connections and updates every 30 minutes. It names Google, Outlook, iCloud and Fastmail. Its paid features include more control over which details are copied.
The project is open source and offers a separate self-hosting guide. Self-hosting is useful when you want to operate the service yourself, but it adds deployment, credential, update and monitoring work. Do not treat it as a hosted unlimited free plan. Verify the current setup requirements against that guide.
Keeper says self-hosted accounts receive its paid sync features without plan limits. You still need your own server and Google or Microsoft OAuth apps. Hosting, updates, backups and access management remain your responsibility.
5. SyncGene — occasional manual reconciliation
SyncGene's pricing page limits Free to one manual synchronization per month. Automatic synchronization is a seven-day preview, rather than an ongoing free automatic service; free calendar sharing is limited to one calendar per account.
That can fit an occasional manual transfer. It is a poor match for keeping work availability continuously aligned. Its pricing page also directs readers toward CiraHub, so confirm which product and subscription you are choosing before building a recurring workflow around it.
Verify the result before trusting it
Use a non-sensitive test event inside the tool's synchronization window. Choose a title such as “Availability check”, with no guests or private notes, and mark the source event Busy.
- Open the actual destination calendar, rather than an overlay of the source. Check the time, title, omitted fields and Free/Busy state.
- Confirm that the Scheduling Assistant or booking tool checks this destination and treats that time as unavailable.
- Move the original event and confirm the existing copy moves. Delete the test original and confirm the expected cleanup.
- For a two-way arrangement, repeat from the other calendar. For a one-way arrangement, an original created at the destination should not flow back.
If a copy is missing, check account access, direction, date window and filters before creating another sync. If it exists but does not block time, inspect its availability and the calendar your booking tool reads. Use the missing-events guide for the next safe checks. A completed connection is not proof of the intended result.
Tools people expect to see here
A free trial can help you test a paid tool. It does not provide ongoing free sync after the trial ends.
OneCal lists paid plans and a 14-day trial without a card on its pricing page. See the OneCal alternative comparison.
CalendarBridge lists paid individual plans and a trial without a card on its pricing page. See the CalendarBridge alternative comparison.
SyncThemCalendars advertises a 14-day trial on its site. See the SyncThemCalendars alternative comparison.
Zapier and IFTTT are automation platforms. Before using either for calendar copying, check the current integration, trigger and action allowances. Creating a copy is only one step. Updates, deletions, recurrence and duplicate prevention also need rules. Our Zapier calendar guide explains these requirements.
What to look for in a free sync tool
1. Does the free allowance continue after the trial? Check the plan details, including automatic versus manual sync. Count accounts, calendars and syncs separately. A free allowance can still have a limited forward window.
2. Does the tool copy events in the direction you need? One-way copying fits a personal-to-work arrangement. Two-way copying fits calendars that both contain originals you want elsewhere. Read-only feeds can only supply events. See sharing versus syncing.
3. Which fields reach the destination? Review titles, descriptions, locations and guests separately. A title of Busy does not guarantee blocked availability. Check the Free/Busy state and the calendar your booking tool reads.
4. How does the tool detect changes? A hosted tool can use provider notifications or scheduled checks. A desktop tool also depends on the computer that runs it. Read the provider-specific limits before relying on a new meeting to block another calendar.
5. What happens when you stop or change tools? Check whether the service can remove its own copies. Before replacing a service, turn off its sync and identify its copies. Preserve original events. Do not run two services over the same calendar pair or delete similar-looking events in bulk.
For more detail, use the calendar sync tool comparison and the Google Calendar app access guide.
Free tiers side by side
These are published allowances, not measured performance results. A connection, calendar and sync can have different meanings across services. Read each profile before treating these limits as equivalent.
| Tool | Ongoing free allowance | Operating requirement | Main limit to check |
|---|---|---|---|
| SYNCDATE Free | 2 accounts, 2 calendars, 1 sync | Hosted; permission to connect the calendars | 30-day forward window; paid appearance options |
| Reclaim Lite | 1 Calendar Sync | Hosted scheduling service | Supported account arrangement and trial features |
| OGCS | Free, open-source software | Windows application; Outlook connection depends on version | Google–Outlook copying, not Google–Google |
| Keeper | 2 linked accounts, 3 connections | Hosted Free or a separate self-hosted installation | Hosted Free updates every 30 minutes |
| SyncGene | 1 manual sync per month | Manual reconciliation after automatic preview | Calendar sharing limited to 1 calendar per account |
Free ways to use Google calendars without a sync tool
Native sharing can give another Google account access to a calendar, subject to permission and company rules. It can solve a combined-view problem without copying anything. A booking tool may also read that shared calendar directly.
An ICS import transfers events once. A subscription shows a separate read-only calendar and refreshes on its own schedule. Neither method should be assumed to put Busy copies in a work calendar. For actual copies between accounts, use the multiple Google calendars guide.
Frequently asked questions
Is there a free way to sync two Google calendars?
Yes. SYNCDATE Free supports one permitted two-calendar sync, with one-way Push or two-way Mirror. Native Google sharing can provide a combined view across accounts. It grants access to the existing calendar rather than automatically making independent copies in the other account. Check which result you need.
Which calendar sync tools actually have a free tier?
SYNCDATE, Reclaim Lite, OGCS, Keeper and SyncGene offer ongoing free options with different limits. SyncGene Free permits one manual sync per month after its automatic preview. OGCS runs on Windows. OneCal, CalendarBridge and SyncThemCalendars advertise trials with paid plans. Check the linked plan pages before connecting.
Is SYNCDATE really free?
Yes. Free covers 2 accounts, 2 calendars and 1 sync with a 30-day forward window. No credit card is required. New syncs copy events as Busy. A two-way Mirror between calendars you own keeps the real titles. You can change either before you start. Larger arrangements and some appearance settings require a paid plan.
Can I sync more than 2 calendars for free?
Check each product's units and limits. SYNCDATE Free allows 2 calendars. Keeper's hosted allowance is 2 linked accounts and 3 connections. Keeper says self-hosting removes its plan limits, but you must run the service. OGCS is a free Google–Outlook tool for Windows, not a direct Google–Google substitute.
Will syncing calendars slow down Google Calendar?
A hosted sync service communicates with the calendar provider outside the calendar app. That alone does not establish a performance guarantee. This guide did not test Google Calendar performance with each tool. Provider limits and retries can delay copies. Check actual copied events before relying on them.
Can I sync personal and work Google accounts without sharing passwords?
Tools that use Google OAuth let each account authorize access without giving its password to the tool. Check the requested access and your company's rules. Review or revoke connections in Google Account permissions. See the app access guide before connecting a work account.
What happens if I delete an event from one calendar?
Distinguish an original event from a copied event. In SYNCDATE, deleting an eligible source original removes its corresponding copies when the sync processes that change. Push never writes back to its source. Mirror carries originals from either calendar; it does not turn every copy into an original. Check deletion behavior with a harmless test event.
Can I sync to multiple destinations from one source?
Yes, if your plan permits the calendars and direction. A SYNCDATE Push can put several destinations in one sync. Free permits 2 calendars and 1 sync, so a source with two destinations exceeds Free. Separate syncs do not relay their copies onward. Read the multiple-calendar guide before choosing the arrangement.
What is the cheapest way to sync 5 Google calendars?
This guide does not establish a cheapest product for every setup. SYNCDATE Free does not cover five calendars. Compare current plan requirements, including the selected direction and its calendar limit. Keeper self-hosting has no licence fee but requires infrastructure and maintenance. OGCS is free for Google–Outlook copying on Windows, not direct copying between five Google calendars.
Choose based on your setup
One hosted personal-to-work arrangement: start with SYNCDATE Free. Review the copied fields and verify blocked availability with the steps above.
Google–Outlook copying on Windows: compare OGCS, with the right Outlook connection for your version.
One Calendar Sync alongside scheduling features: compare Reclaim's free allowance. The Reclaim alternative page explains the difference in scope.
A service you operate yourself: compare Keeper's self-hosting requirements, including hosting and account authorization. Hosted Free has separate limits.
Occasional manual reconciliation: SyncGene Free can fit, if one manual sync per month meets your need.
For a work and personal arrangement, read sync personal and work Google Calendar. For booking conflicts, read avoid double-booking Google Calendar. For a wider shortlist, use the calendar sync tool comparison.
If you replace an existing tool, stop its sync before starting the replacement. Check its cleanup option and preserve original events. Then verify the new destination copies and actual availability.