Best OneCal Alternatives for Calendar Sync (2026)

Quick answer: SYNCDATE is worth evaluating if you want a permanent free entry for two accounts and two calendars, or need its particular appearance, filter and direction controls. We make SYNCDATE, so weigh this as our view. If OneCal already gives you the calendar view, booking links and copying you need, keeping a working setup can be the better choice.

The choice should follow your actual arrangement: which calendars receive copies, what each destination may reveal, which calendar supplies scheduling availability, and what your employer permits. A feature list cannot establish that a particular tenant will approve a connection.

Vendor-owned pages checked October 12, 2026 are linked below. We have not performed a comparative live-provider benchmark.

First decide whether you need copies

For your own planning, a combined calendar view may be enough. Microsoft explains showing multiple calendars in Outlook. Hiding a calendar from that view does not delete it, and adding a view does not put events in another mailbox.

Copies matter when colleagues or a booking tool read one calendar and need your commitments from another account to occupy time there. Check the exact calendar they use before choosing a sync tool.

Four alternatives and when each fits

1. SYNCDATE: a free starting arrangement and configurable copies

Free supports 2 connected accounts, 2 calendars and 1 sync, with a 30-day forward window. Plus supports 5 accounts, 20 calendars across 5 syncs, and up to 4 calendars in one Mirror or 10 in one Push. Pro supports 20 accounts, 100 calendars across 20 syncs, and up to 5 calendars in one Mirror or 20 in one Push. The total-calendar allowance is not the number that fits inside a single Mirror. Check every limit and current pricing.

SYNCDATE connects Google, Microsoft, iCloud, Fastmail and Nextcloud calendars, and read-only iCal feeds as one-way sources. Google and Outlook changes usually reach the other calendar in under a minute; CalDAV calendars are checked about every 10 minutes; iCal feeds on a schedule. Delays and retries remain possible.

Review appearance explicitly. Copies show as Busy whenever a calendar is not fully yours; two-way mirrors between your own calendars keep titles unless you switch. A Busy title does not itself mark time unavailable. Choose Free/Busy separately and omit descriptions, locations and guests when they should not enter another account. Pro supports appearance settings for each destination; Plus rules can make supported fields depend on the source calendar. Review asymmetric privacy.

2. CalendarBridge: evaluate its connected-calendar and scheduling package

CalendarBridge publishes Google, Microsoft and iCloud copying, a unified calendar and scheduling features. Its individual pricing page distinguishes calendar counts, sync connections and viewing limits. Verify the chosen arrangement against all three; a viewing allowance is not a sync allowance. Compare its current subscription with the features you would actually use.

3. SyncThemCalendars: evaluate its sync-connection model

SyncThemCalendars lists Google, Outlook and iCloud, one-way and multi-way copying, and configurable copied details. Its plans count syncs rather than using SYNCDATE's account and per-Mirror limits. Its site offers a 14-day trial. Map the connections you need before comparing plans.

4. Reclaim: evaluate scheduling alongside calendar sync

Reclaim combines calendar sync with scheduling features. Compare it when arranging tasks and time is part of the job, then check the provider and plan conditions for the specific sync. Our Reclaim comparison explains that decision separately.

What OneCal currently publishes

OneCal's pricing lists a 14-day trial without a card, calendar-count tiers, booking links and a unified calendar view. Its sync page describes copied-field controls, filtering, private flags and reminders. Those are documented capabilities, not omissions.

Its CalDAV integration page explicitly names Fastmail and Nextcloud. CalDAV is therefore not an exclusive SYNCDATE advantage. Verify the particular server and credentials before switching. For Internet calendar feeds, ask about the exact read-only source you need rather than treating an absent statement as proof of no support.

You do not have to pay before evaluating OneCal's trial. A trial and SYNCDATE's continuing Free plan are different evaluation choices.

Switch without two tools copying the same calendars

1. Record the original calendars, source and destination accounts, directions, copied fields, filters and date window. Identify the calendar colleagues or booking tools actually check.
2. Export or otherwise preserve the originals using your provider's supported method. An export is a recovery aid; importing it into the same calendars can create duplicates.
3. Test SYNCDATE on separate, non-sensitive calendars where possible. Review permissions and appearance before starting: the first run can copy existing eligible events.
4. Before enabling SYNCDATE on the production pair, stop the old tool from writing to that pair. Check its cleanup options first. OneCal's calendar-sync FAQ says deleting a sync offers an option to remove its clones. Removal can temporarily reopen previously blocked time. Keep the original events; never bulk-delete events merely because they look similar.
5. Inspect the destinations after cleanup. Retained copies from the old tool are not automatically adopted as SYNCDATE copies. If you cannot confidently distinguish originals from copies, stop and ask the old vendor or SYNCDATE support.
6. Start one reviewed SYNCDATE arrangement. Create a harmless Busy test event, move it, and delete it. Verify the corresponding destination copy, its omitted details and actual Free/Busy state. Repeat in the other direction for Mirror.
7. Check the Scheduling Assistant or booking tool against the destination calendar. Cancel the old subscription only after verifying the replacement and the vendor's separate cancellation procedure.

Two active services on the same pair can create duplicate copies or copy each other's output. There is no universal migration time or risk-free handover. If you need continuous availability during the switch, plan the gap explicitly before removing old blocks.

Choose the matching setup: Google–Outlook method choice, two Outlook accounts, iCloud with Outlook, or one Mirror across several accounts.