A CalendarBridge alternative for Google and Outlook calendars
CalendarBridge and Caltsu both copy your availability between calendars. CalendarBridge also covers iCloud and includes scheduling pages, a unified calendar app and an AI scheduling assistant. Caltsu only syncs, copies nothing but the time, and has one €5 plan with no limit on calendars.
- Main job
- CaltsuCalendar syncCalendarBridgeCalendar sync, with scheduling pages, a unified calendar app and an AI scheduling assistant on every plan
- What the other calendar receives
- CaltsuA block with the start and end time, the title Busy or your own text, and a note naming the source calendar. Never the event title, attendees, location, notes or meeting link.CalendarBridgeConfigurable. All details, only Busy, or somewhere in between.
- Sync direction
- CaltsuTwo-way between every calendar in a sync groupCalendarBridgeOne or both directions
- Google Calendar
- CaltsuYesCalendarBridgeYes
- Microsoft 365 and Outlook
- CaltsuYesCalendarBridgeYes, for Microsoft 365 business plans, Exchange Online and Outlook.com. CalendarBridge says Microsoft 365 Personal and Family cannot be supported.
- Apple iCloud
- CaltsuNot yetCalendarBridgeYes. CalendarBridge says iCloud changes sync every 5 to 10 minutes.
- Connected calendars
- CaltsuNo limitCalendarBridge2 synced connections on Basic, 20 on Premium, 56 on Pro. The yearly plan cards describe these as 2, 5 and 8 calendars.
- Price
- Caltsu€5 per month or €48 per year. One plan, 14-day trial without a card.CalendarBridgeBasic $5, Premium $10, Pro $40 a month, or $4, $8 and $32 a month billed yearly. Free trial without a card.
- Where the servers are
- CaltsuPostgreSQL in Frankfurt, GermanyCalendarBridgeIn the US, according to CalendarBridge's privacy policy
| Topic | Caltsu | CalendarBridge |
|---|---|---|
| Main job | Calendar sync | Calendar sync, with scheduling pages, a unified calendar app and an AI scheduling assistant on every plan |
| What the other calendar receives | A block with the start and end time, the title Busy or your own text, and a note naming the source calendar. Never the event title, attendees, location, notes or meeting link. | Configurable. All details, only Busy, or somewhere in between. |
| Sync direction | Two-way between every calendar in a sync group | One or both directions |
| Google Calendar | Yes | Yes |
| Microsoft 365 and Outlook | Yes | Yes, for Microsoft 365 business plans, Exchange Online and Outlook.com. CalendarBridge says Microsoft 365 Personal and Family cannot be supported. |
| Apple iCloud | Not yet | Yes. CalendarBridge says iCloud changes sync every 5 to 10 minutes. |
| Connected calendars | No limit | 2 synced connections on Basic, 20 on Premium, 56 on Pro. The yearly plan cards describe these as 2, 5 and 8 calendars. |
| Price | €5 per month or €48 per year. One plan, 14-day trial without a card. | Basic $5, Premium $10, Pro $40 a month, or $4, $8 and $32 a month billed yearly. Free trial without a card. |
| Where the servers are | PostgreSQL in Frankfurt, Germany | In the US, according to CalendarBridge's privacy policy |
CalendarBridge details come from its public website, checked September 2026. Plans change, so confirm on their site before you decide.
When CalendarBridge fits better
- You need iCloud calendars, or a calendar you can only reach through an .ics link, in the sync today.
- Some syncs should run one way, or copy full event details.
- You want scheduling pages and an AI assistant from the same vendor, or need a HIPAA business associate agreement, which CalendarBridge offers on Premium and Pro.
When Caltsu fits better
- Client or employer calendars must never receive a title, attendee or location, with no setting that could change that.
- Your IT team wants the database in the EU and a short list of OAuth permissions to review.
- You connect three or more calendars. CalendarBridge Basic covers two, so that means Premium at $10 or Pro at $40 a month. Caltsu stays at €5.
What a client calendar sees from Caltsu
Every copied event becomes a block with its start and end time. The title defaults to Busy and you can change the text. The block description says which of your calendars it came from, such as "Blocked time from work@example.com". There is no setting that copies the event title, attendees, location, notes or meeting link, so nobody can switch it on by mistake.
Permissions and data handlingClient calendar, Tuesday
Steering group09:00-10:00
Busy10:30-11:15
Busy13:00-14:30
Sprint review15:00-16:00
Common questions
- Is Caltsu cheaper than CalendarBridge?
- For two calendars they cost about the same: CalendarBridge Basic is $5 a month and Caltsu is €5. From three calendars on, CalendarBridge needs Premium at $10 or Pro at $40 a month, which is $8 or $32 billed yearly. Caltsu is €5 a month or €48 a year for any number of Google and Microsoft calendars.
- Does Caltsu sync iCloud calendars like CalendarBridge?
- Not yet. Caltsu syncs Google Calendar, Google Workspace, Microsoft 365 and Outlook.com. If you need iCloud in the sync today, CalendarBridge supports it.
- Where do Caltsu and CalendarBridge keep their data?
- Caltsu's database runs in Frankfurt, Germany. CalendarBridge's privacy policy, updated 19 March 2026, says its services are hosted and operated in the US, and that it stores event identifiers rather than the content of your calendars.
- How do I switch from CalendarBridge to Caltsu?
- Start a Caltsu trial, connect the same Google and Microsoft accounts and put the calendars in one sync group. Then delete your sync connections in CalendarBridge. CalendarBridge says it removes the event copies it created when you do, so the same time is not blocked twice.
- Do both have a free trial?
- Yes, and neither asks for a card. Caltsu's trial runs 14 days. Neither lists a free plan.
Try it on your own calendars.
Other comparisons: OneCal, Reclaim.ai, Clockwise, Cal.com