How to Sync Google Calendar with Proton Calendar
Keep Google and Proton calendars perfectly aligned — automatically, in near real-time.
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The problem
Google Calendar and Proton Calendar don't natively talk to each other. Google Calendar can subscribe to external iCal feeds but only refreshes every 12–24 hours, and subscribed calendars are read-only — there's no two-way sync. Meanwhile, proton Calendar encrypts all event data end-to-end. iCal sharing is supported but limited by Proton's privacy-first architecture. The result: you end up double-booked, or you waste time manually copying events between Google and Proton.
Common issues
- Google Calendar's iCal subscription only refreshes every 12–24 hours, so changes from other calendars appear with significant delay
- Proton Calendar's end-to-end encryption means shared iCal feeds contain less metadata than other providers
- Events added to a subscribed calendar inside Google don't sync back to the source calendar
- Proton Calendar doesn't support subscribing to external iCal feeds (import only)
What people try
The most common workaround is subscribing to an external iCal feed via Google Calendar settings. On the Proton side, people try exporting events from Proton as .ics files and importing them into the other calendar. Some users resort to exporting .ics files and importing them manually, or use automation tools like Zapier to bridge the gap.
Why manual approaches fail
Google only polls external feeds roughly once a day, meaning last-minute changes won't show up in time to prevent conflicts. On the other side, this is a one-time snapshot, not a live sync — you'd need to repeat the export/import every time something changes. Manual exports are snapshots — they go stale immediately. Automation tools add complexity, cost, and still can't guarantee real-time sync. None of these approaches reliably prevent double bookings.
How iambusy solves this
iambusy connects Google Calendar and Proton Calendar through their iCal feeds and syncs busy time automatically. Open Google Calendar Settings, select the calendar you want to sync, scroll to 'Secret address in iCal format', and copy the URL. In Proton Calendar settings, select the calendar, enable 'Share via link', and copy the iCal URL. Paste both into iambusy and your availability stays aligned across both calendars within seconds — no passwords shared, no admin access needed.
Connect your calendars
Paste the iCal URL from each calendar. Takes 30 seconds per calendar, no passwords required.
Set your sync rules
Choose what to share — full details, titles only, or just Busy blocks to keep things private.
Stay in sync automatically
Changes propagate in seconds. No manual work, no double bookings, no missed meetings.
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Frequently asked questions
Can I sync Google Calendar with Proton Calendar for free?
iambusy offers a 7-day free trial with full access. After that it's $5/month or $50/year — less than the cost of a single double-booked meeting.
Does syncing Google and Proton require sharing my password?
No. iambusy uses iCal feed URLs which are read-only. Your calendar credentials are never shared or stored.
How fast do changes sync between Google Calendar and Proton Calendar?
Most changes sync within seconds through webhooks and smart polling. This is significantly faster than native iCal subscription refresh rates.
Will my event details be visible when syncing Google and Proton?
You control what's shared. Use Busy-only mode to hide all event details, or choose to sync titles, descriptions, or full event information.
Related guides
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