If you keep calendars at more than one company, SYNCDATE is the one we recommend: Google, Outlook, iCloud and CalDAV together, privacy by default (copies show as Busy unless it's a two-way Mirror between calendars you own), free for 2 calendars and 1 sync, no credit card. We make SYNCDATE, so weigh this as our view; the competitor facts below were checked on 18 September 2026. If that is your setup, start on the free plan; if you need more than 2 calendars or more than one sync, check the plan limits first.
A calendar sync tool is useful when you need events from separate accounts to occupy time on the calendars your colleagues or booking tools actually check. For a consultant with several company accounts, the choice depends on which calendars need to receive events, what details each destination may reveal, and how many calendars fit in one sync.
SYNCDATE fits professionals who need Google, Outlook and CalDAV calendars to share availability with control over event details. If you only need to see calendars side by side, a native overlay is enough; copying is what marks you busy where other people look. If you need automatic task scheduling or booking links, compare those features separately from event copying.
This comparison is written by SYNCDATE's founder. Vendor facts were checked against the linked official pages; recommendations are our judgment, not the result of a comparative performance benchmark. We do not infer that a competitor lacks a feature merely because a page does not mention it.
Choose for your calendar setup
Work and personal calendars
For one work calendar and one personal calendar, decide whether personal commitments should only block work time, or whether both calendars should receive each other's events. SYNCDATE's Free plan covers 2 accounts, 2 calendars and 1 sync, with a 30-day forward window. It is a way to test that exact arrangement without paying.
Use the personal-to-work Busy setup for one-way blocking. If you need real titles on your personal calendar but masked copies at work in the same sync, per-calendar appearance settings require Pro. Free and Plus use shared appearance settings within a sync.
Several company or client calendars
If every calendar must show the others' commitments, use one two-way sync containing all the calendars. Three or four calendars fit in one Mirror on Plus; five require Pro. The total plan allowance is not the size of a single Mirror: Pro's 100-calendar allowance does not mean a 100-calendar two-way sync.
Start with the multi-account Mirror setup. Separate A↔B and B↔C syncs do not carry A's copies onward to C. If you have more than five calendars that all need to mirror each other, the standard per-sync limit does not fit that requirement; check the limits before paying.
If you only need a consolidated personal view, use a one-way client-calendar hub. That collects events in the hub; it does not block time back on the client calendars. The recipe keeps original titles, so choose a hub whose readers are allowed to see them.
iCloud personal calendar and a company Google or Microsoft account
Use a writable iCloud CalDAV connection when events must reach iCloud. An ICS subscription is a read-only source. Follow the iCloud setup and verification guide, and check that your employer permits the connection. No plan can bypass an administrator's app restrictions.
Scheduling links or automatic rescheduling
If the job is to let clients book a slot, evaluate scheduling-link features. If the job is to find time for tasks and move flexible meetings, evaluate a scheduling suite such as Reclaim. SYNCDATE's event-copying workflow solves a different part of that problem; do not buy it expecting an AI scheduler.
Seven tools compared
Prices below use the billing basis each vendor publishes. An annual per-user price is not the same purchase as a monthly individual plan. Follow the source link before subscribing; currencies, taxes and promotions may differ.
1. SYNCDATE — controlled availability across your own accounts
Connect Google Calendar, Outlook/Microsoft 365 and CalDAV accounts, including iCloud, Fastmail and Nextcloud. iCal feeds can be sources but cannot receive writes. Copies show as Busy unless it's a two-way Mirror between calendars you own, which keeps the real titles; you can change either before you start. Review the appearance settings before including descriptions, locations or guests.
Capacity: Free 2 accounts, 2 calendars, 1 sync; Plus up to 5 accounts, 20 calendars in total, 5 syncs; Pro up to 20 accounts, 100 calendars in total, 20 syncs. Plans are flat per account, not per user.
Plan fit: Free is one two-calendar setup. Plus allows 5 accounts, 5 syncs and 20 calendars across syncs, with up to 4 calendars in one Mirror or 10 in one Push. Pro allows 20 accounts, 20 syncs and 100 calendars across syncs, with up to 5 in one Mirror or 20 in one Push. Complexity and write-permission checks also apply. Pro adds per-calendar appearance settings and an unlimited forward window; Plus reaches one year ahead.
Delivery: Google and Outlook changes usually reach the other calendar in under a minute; CalDAV calendars are checked about every 15 minutes; iCal feeds on a schedule. Notification delivery, provider limits and retries can add delay.
Check before choosing: a feed cannot be one side of a two-way sync; separate syncs do not chain; no plan bypasses company access policies. Compare current prices and all plan limits.
2. OneCal — sync with booking links and a unified view
OneCal lists Google, Outlook and iCloud, one-way and multi-way sync, event-detail controls, booking links and a unified view. Its pricing page lists a 14-day trial, then paid plans. Starter is $5 per user/month billed annually for 2 calendars; Essential is $10 for 5; Premium is $25 for 50.
Check before choosing: count calendars per user and compare the billing interval. OneCal's detailed table makes removal of scheduling-link branding Premium-only, despite broader wording in its plan cards. Confirm any feature that determines your purchase. OneCal pricing and feature table.
3. CalendarBridge — sync plus scheduling and calendar views
CalendarBridge lists Google, Microsoft and iCloud support, with periodic rather than notification-driven updates for iCloud and Internet calendars. Its individual plans cover 2, 5 and 8 synced calendars. Monthly prices are $5, $10 and $40; annual billing is listed as $4, $8 and $32 per month.
Check before choosing: the number of calendars visible in its unified view is a separate allowance from synced calendars. Confirm the allowance for the job you need. Individual pricing and supported calendar types.
4. Reclaim — scheduling tasks, habits and meetings alongside sync
Reclaim combines Calendar Sync with tools for focus time, habits, tasks and meetings. Its free Lite plan includes one Calendar Sync; the pricing page lists Starter at $10 per seat/month on yearly billing.
Check before choosing: compare the scheduling range, Calendar Sync count and seat requirements for your workflow, rather than treating this as a like-for-like sync-only subscription. Reclaim plans.
5. OGCS — a free desktop option for Outlook and Google
Outlook Google Calendar Sync is a free, open-source Windows application supporting one-way and two-way synchronization. Its v2 line requires Classic Outlook; the vendor lists Outlook Online support in v3, currently offered as an alpha.
Check before choosing: choose the release that supports your Outlook account and consider whether keeping a desktop application running fits your working day. It serves a different setup from a hosted service that runs while your computer is off. OGCS features and requirements.
6. SyncThemCalendars — source-and-target sync configurations
SyncThemCalendars lists Google, Outlook and iCloud, one-way and two-way configurations, and controls that hide copied event details. It offers a 14-day trial followed by a paid subscription.
Check before choosing: price the sync configurations you need using its current plans. Do not assume that a vendor's sync count and another vendor's calendar count measure the same thing. SyncThemCalendars.
7. Zapier — calendar events inside a wider automation
Zapier offers Google Calendar and Microsoft Outlook triggers and actions. It is worth considering when a calendar event should also trigger a workflow in another application.
Check before choosing: a create-event automation is not by itself a complete two-way sync. Specify what should happen on edits, deletions, recurring events and retries, and check the task allowance and trigger timing for your chosen workflow. Google Calendar and Outlook integrations.
Compare the arrangement, not just the headline price
| What you need | What to verify before paying |
|---|---|
| Block personal time at work | Copies land on the calendar checked for availability; private fields stay hidden |
| Share availability across clients | Every required calendar receives events directly; no unsupported chain of copies |
| Keep full details in one destination | Per-destination appearance settings and the plan that includes them |
| Use iCloud in both directions | Writable account connection; expected polling delay; test both directions |
| Plan months ahead | Forward sync window, including any exceptions for recurring events |
| Switch providers | Cleanup choices, existing copies and a test with one calendar pair |
Sync speed matters, but no sync removes every booking window
There is always time between an event changing and another system seeing the copy. A notification starts work; it does not prove that the destination has been updated. Compare the full path, including iCloud polling and the booking tool's own refresh.
Before relying on a setup, create a harmless test event in the selected source calendar, verify its destination copy and privacy, change its time, then delete it. For a two-way setup, repeat from the other calendar. Check availability in the booking tool you actually use. A calendar overlay alone does not prove that tool checks all your commitments.
Switch without two services writing the same events
Read the old tool's cleanup policy first. Test the replacement on a limited setup, then stop the old writer before connecting the same production calendars to the new one. Decide whether old copies should be removed. Running two tools on the same calendar pair can introduce duplicates; it is not a reliable migration test.
When paying for SYNCDATE makes sense
Pay for a requirement you have identified: more accounts, a larger supported arrangement, a longer forward window, or per-calendar appearance. A consultant with three writable company calendars needs at least Plus for one shared Mirror. Someone with only work and personal calendars may still need Pro if each destination must show different details in the same sync.
If Free covers your arrangement, test it there first. If you only want to see several calendars in one app, a native overlay may already solve the problem. Check the plan for your setup, then use the linked recipe to build it.
Start with the setup that fits your calendars
For Google and Outlook, choose between native viewing and event copies, then use the two-way setup if both calendars need copies. For two Microsoft accounts, follow the two-Outlook guide.
For private personal commitments at work, review the masked-title setup and its actual Free/Busy behavior. For several client accounts, choose a one-way collection or a multi-account Mirror. Check the plan limits for your arrangement, and verify one harmless event before relying on it.
Frequently asked questions
What is the best calendar sync tool for multiple company accounts?
If you keep calendars at more than one company, we recommend SYNCDATE (we make it, so weigh that as our view): Google, Outlook, iCloud and CalDAV together, privacy by default (copies show as Busy unless it's a two-way Mirror between calendars you own), free for 2 calendars and 1 sync. For any tool, choose by the required arrangement and company permissions. In SYNCDATE, three or four calendars in one two-way Mirror need Plus; five need Pro. Every calendar must be writable and every account must permit the connection. Separate syncs do not pass copied events onward.
Is a free calendar sync plan enough?
It can be. SYNCDATE Free covers two accounts, two calendars and one sync with a 30-day forward window. More accounts, longer coverage or different appearance per destination may require a paid plan. Check the specific limit before upgrading.
Can a calendar sync tool guarantee no double-bookings?
No. Processing delays and booking-tool settings leave a window for conflicts. Verify copied events and confirm that the booking tool checks their destination calendar. A successful connection alone is not proof of complete availability.
Can I use the same tool for iCloud, Google and Outlook?
SYNCDATE supports all three. Connect iCloud as a CalDAV account for two-way use; an iCal URL is read-only. A three-calendar Mirror needs Plus or above. OneCal and CalendarBridge also list all three providers; compare their current limits and settings.
Does syncing calendars also reschedule meetings?
Copying events and rescheduling meetings are different jobs. SYNCDATE copies events according to your configuration. If you want tasks and flexible meetings rearranged automatically, evaluate a scheduling suite separately.