Calen1 vs OneCal vs CalendarBridge: an honest calendar sync comparison

Updated August 2026 · the Calen1 team

If you live with two or three calendars — work in Microsoft 365, personal in Google, home in iCloud — you know how the story ends: someone books you into a gap that was actually taken on the other calendar, and you find out ten minutes beforehand. The way to fix it isn't remembering harder, it's a tool that syncs your calendars across accounts. The three most often compared today are Calen1, OneCal and CalendarBridge.

A warning up front, because it changes how you should read this: this comparison is written by the Calen1 team. That's why Calen1's numbers are exact and you can check them on our pricing page. We talk about OneCal and CalendarBridge in general terms and tell you what to check on their sites: they're products that adjust prices and features often, and we'd rather not give you a figure that's a lie in three months.

The one-line summary: all three solve the underlying problem. Calen1 charges in Mexican pesos, is built in Spanish first and bets on doing a few things well; OneCal and CalendarBridge are US products, more established, with a wider integration catalogue and billing in dollars. Which suits you comes down to six concrete criteria.

The six criteria that actually decide it

Comparison pages tend to count features. That's no use: almost nobody uses half of them. What decides whether a sync tool helps you or gets in your way is this:

• Supported providers. Does it cover exactly the accounts you have, not the ones you might have?
• Real two-way sync. That create, edit and delete are reflected on both sides. Deletion is the hard test.
• Duplicate handling. What happens when you connect for the first time, and whether a copy can get copied again in a loop.
• Privacy. Whether your personal calendar shows up on the work one as a "Busy" block or with the full title on display.
• Booking page. Whether you need one, whether it's included, and in which plan.
• Price and currency. Not the number, but what you actually end up paying a month in your currency, and how it scales.

Everything else — conferencing apps, unified views, extensions — is nice, but it's rarely the reason a tool fails you.

Supported providers: all three cover Google, Microsoft and iCloud

On the basics they're tied: all three tools work with Google Calendar, Outlook/Microsoft 365 and iCloud. If your combination is "personal Google + work Microsoft", any of the three will do and you'll have to decide on other criteria.

The difference is in the iCloud detail, which is the most awkward provider of the three for everyone. In Calen1, iCloud connects over CalDAV, which means generating an app-specific password at account.apple.com (two-factor authentication required). Calen1 never asks for or stores your normal Apple password. You can also choose with a button whether iCloud runs one way (out to Google or Microsoft only) or both ways, and events arriving from iCloud land in a new, dedicated calendar called "iCloud (Calen1)" so they don't get mixed in with yours.

What Calen1 doesn't cover today: Yahoo, Fastmail, Nextcloud or any calendar outside Google, Microsoft and Apple. If you depend on one of those, ask OneCal and CalendarBridge directly before paying, because Calen1 doesn't compete there.

Two-way, deletions and duplicates: where syncs break

"Two-way sync" sounds obvious until you test it. Calen1 mirrors Google and Microsoft 365 in both directions: you create, edit or delete on one side and the change reaches the other. It also handles recurring events as a series, not as loose copies (which matters when you move the weekly meeting), along with all-day events and time zones.

The classic problem with tools like these is duplicates: the copy the tool created in calendar B gets detected as a new event and copied back to A, and on it goes until your week looks like a wall. Calen1 marks every copy it creates internally and records which event on the other side it corresponds to, which is why a copy doesn't bounce back. And on first connection it reconciles: it pairs up the events that already existed on both sides instead of duplicating them.

There's one difference you should be clear about. OneCal and CalendarBridge market themselves as real-time sync. Calen1 isn't: the sync runs by itself roughly every two minutes. For 95% of cases that's irrelevant, but if your operation depends on a change appearing in the same second on the other calendar, those couple of minutes could be the reason to go elsewhere.

Test it yourself, with any of the three, before trusting it with your calendar: create an event, edit it, delete it, move a whole recurring series, and schedule an all-day event with someone in another time zone. If all five pass, the tool works.

Privacy: what shows of your personal calendar on the work one

This is the criterion people discover late and painfully. If you sync your personal calendar with your work one without privacy control, your colleagues can read the titles of your appointments: the doctor, the school, the interview.

Calen1 has privacy mode: the personal event appears on the work calendar as "Busy" only, blocking the slot without revealing the title or description. It's a checkbox, not a configuration trick.

All three tools offer some way of hiding details, so what you should compare isn't whether it exists but how fine the control is: whether you can turn it on per calendar rather than across the board, and exactly what gets copied into the destination event (title, location, guests, video call link). Check it with a real test event before syncing your entire personal life.

Booking page: useful, but not everyone needs one

All three options include some form of Calendly-style booking page. In Calen1 it's called Agenda Pro and it's only in the Pro plan. What it does: it publishes a page of yours that offers only the slots free across all your connected calendars at once, so nobody books you over something sitting in the other account. Guests pick their time zone and see the times in it, and the page shows in English or Spanish depending on the browser of whoever opens it. You decide which calendars count as "busy", your working hours, the meeting length, the buffers between meetings and the minimum notice. You add your logo and your colour.

In OneCal and CalendarBridge booking pages also exist and are a central part of the product; what varies between them is how many pages are included and in which plan, so do check that on their sites.

Practical advice: if you already use Calendly, Cal.com or Microsoft's own Bookings and you're happy, don't pay twice for the same thing. In that case the cheapest plan of whichever sync tool you choose is enough — in Calen1, the Base plan — and you leave bookings where they already are.

Price and currency: the part almost nobody compares properly

Calen1 charges in Mexican pesos, per user, and there are two plans:

• Base: $50 MXN a month or $500 MXN a year. Includes syncing Google, Microsoft 365 and iCloud, privacy mode and multiple accounts.
• Pro: $149 MXN a month or $1,490 MXN a year. Everything in Base plus Agenda Pro.

The annual plan works out to paying for ten months: two free. And something we say up front because it shows up sooner or later: Calen1 has no free plan and no automatic free trial. If the way you decide is by trying something for two weeks without handing over a card, OneCal and CalendarBridge will suit you better there, because they offer free trials; confirm the length on their sites.

The other underlying difference is currency. OneCal and CalendarBridge charge in dollars and their pricing scales with how many calendars you connect, not just per person. To compare properly from Mexico, do three quick sums: one, how many calendars you'll actually connect (that's where dollar pricing takes off); two, the day's exchange rate plus whatever your bank charges for foreign purchases, which is added every month; three, if you need a Mexican tax invoice, ask before signing up, whichever tool it is. OneCal's and CalendarBridge's exact amounts change often: take them from their own pricing page on the day you decide, not from a comparison.

Who each one suits, and when Calen1 isn't your option

Calen1 suits you if you're a freelancer, a consultant or a small company in Mexico; you invoice and spend in pesos and don't want a subscription that rises with the dollar; your combination is Google, Microsoft 365 and iCloud; you want privacy mode solved out of the box; and you'd rather have a tool that does a few things and does them completely.

OneCal or CalendarBridge suit you if you're going to connect many calendars in more unusual combinations; you need integrations Calen1 doesn't have; it matters to you that the sync is advertised as instant; you want to try before you pay; or your spending is already in dollars and charging it to a US entity simplifies your accounting.

Calen1 isn't your option if you need any of these, which simply don't exist in the product today:

• A mobile app: Calen1 is web.
• Team features, roles or calendars shared between several users.
• Slack, Teams, Zoom or Notion integration.
• Syncing tasks, contacts or email. Calen1 moves calendar events only.
• Yahoo, Fastmail or Nextcloud calendars.
• Trying it without paying.

To decide in fifteen minutes:

1. Write down the accounts you're going to connect and how many calendars that is in total.
2. Note whether you need a booking page or already have one.
3. Open all three pricing pages and work out the annual cost in your currency, bank fees included where they apply.
4. Rule out any that fail your must-have cases (team, mobile app, unusual provider).
5. With whichever is left, run the five-step test: create, edit, delete, recurring series and an all-day event across time zones.