Office 365 to Google Calendar Integration: The One-Step Fix

If you searched for an "Office 365 Google Calendar integration", you probably expected a button somewhere that connects the two. There isn't one. Microsoft and Google don't ship a native calendar integration — so the standard advice is to publish your Microsoft 365 (Office 365) calendar as an ICS feed and subscribe to it from Google Calendar. That is the integration. The problem is that it breaks in three predictable ways.

Why the Office 365 → Google Calendar integration looks broken

Microsoft 365 and Office 365 are the same product — Microsoft renamed Office 365 to Microsoft 365 — and both publish the exact same kind of calendar feed. That feed has three issues Google Calendar struggles with:

• Wrong time zones. The feed uses Windows time-zone names like W. Europe Standard Time instead of the standard IANA names (Europe/Berlin) that Google expects, often without a matching VTIMEZONE block. Google falls back to UTC, so every event shifts by your time-zone offset — typically an hour or two off.
• It stops updating. Google refreshes subscribed calendars on its own schedule (often only every 8–24 hours) and gives you no manual refresh button. Combined with quirks in Microsoft's feed, the calendar can look stuck or go empty.
• It's one-way. ICS subscription is read-only. Changes you make in Google never flow back to Outlook — which surprises people expecting a true two-way sync.

None of these are settings you can toggle off in Outlook. The feed itself has to be rewritten.

The one-step fix

CalConverter takes your Microsoft 365 / Office 365 ICS link and serves back a clean, standards-compliant feed: the Windows time-zone names swapped for standard IANA zones, valid VTIMEZONE blocks added, and correct line endings throughout. Google accepts it and keeps refreshing it — no more re-importing, no more shifted times.

Step by step

1. Publish your Outlook calendar. In Outlook on the web, go to Settings → Calendar → Shared calendars, publish your calendar with "Can view all details", and copy the ICS link. (Stuck here? See how to find your Outlook ICS link.)
2. Convert it. Paste that link into CalConverter and copy the Google-compatible URL it returns.
3. Subscribe in Google Calendar. Open Other calendars → Subscribe from URL, paste the converted URL and save.

For the full walkthrough, see Add a Microsoft 365 calendar to Google Calendar.

"But I need a two-way sync"

Be honest with yourself about what you actually need. If the goal is to see your work calendar correctly inside Google Calendar or on your phone, a clean one-way feed is the better choice — it never creates the duplicate or conflicting events that two-way sync tools are notorious for. True two-way sync (edit in either place) requires a paid service with full account access to both calendars; most people don't need that.

Going from Google Calendar to Office 365 (the reverse direction)

Need it the other way — a Google calendar showing up inside Outlook or Office 365? That direction is also a one-way ICS subscription, just pointing the opposite way. Publish the Google calendar's secret ICS address (Google Calendar → Settings → your calendar → Integrate calendar), then add it in Outlook on the web via Add calendar → Subscribe from web. CalConverter converts in the Office 365 → Google and Apple direction; for this reverse case you subscribe to Google's own feed directly.

If it still shows the wrong time or stops updating

Those are the two classic failure modes, and each has its own fix:

• Times are off by an hour or more → Google Calendar shows wrong times for Outlook events.
• The calendar appeared once and then froze → Outlook calendar not syncing with Google Calendar.