Two-way sync between Notion and Apple Calendar
Two-way sync means an edit in Apple Calendar changes the Notion page and an edit in Notion changes the event. Calnio does both, with one switch on each sync. This article covers what moves, what happens when both sides change, and what deleting does.
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What moves
The title and the date: start, end and whether the event is all day. Calnio keeps what both sides agreed on at the last check and compares each field against it. A title you rename in Notion and a time you drag in Apple Calendar between two checks both survive, because they are different fields.
Nothing else travels. Location, notes and alarms stay in Apple Calendar, and Notion properties other than the title and the date stay in Notion.
Switch it on
- Open Syncs in Calnio and find the card of the sync.
- Switch Two-way sync on. The label reads Two-way sync is on once it is.
- Wait for the next check, which runs every 5 minutes by default.
Two-way needs the paid plan or the trial, and a Notion connection that may write into your pages. If you connected Notion before two-way existed, the card tells you to reconnect it on Connections. Accounts made before 2 November 2026 on the free plan sync one way.
When both sides changed
If the same field changed on both sides since the last check, the later edit wins and Notion wins a tie. Notion records edit times to the minute, so Calnio rounds the event's modified time down to the minute before comparing.
New events become pages
An event you add to the calendar becomes a new page in the database. Three conditions apply. The calendar has to belong to a single sync, because with two databases Calnio cannot tell where the event goes. The event has to be created after you switched two-way on, so your existing events do not turn into pages. And it cannot repeat or have guests.
What deleting does
Deleting an event sends its page to the Notion trash, unless the page was edited since the last check. Deleting a page in Notion deletes its event.
An event deleted in Apple Calendar while its page was edited in Notion comes back. A deletion carries no time, so it cannot win a race against an edit.
Ticking a task done in Notion changes nothing in the calendar.