Sync Outlook and Google Calendar

If you work in Microsoft Outlook (Microsoft 365 or Exchange Online) and also use a Google calendar – privately or for a second project – you know the pain: a booking in one calendar is invisible in the other, and suddenly a meeting lands on a blocked slot. The usual Microsoft or Google guides only half-solve it: an iCal subscription is one-way and slow, a full import copies all your private details across unfiltered.

Kalender Sync instead connects Outlook and Google cleanly via the official APIs – in real time, one- or two-way, and you decide how much the other calendar gets to see. No Outlook add-in, no browser extension, no admin rights for the standard case.

🎯 Why connect

Who connects Outlook with Google Calendar – typical situations

The most common case is employees tied to a Microsoft 365 company account at work who have run a personal Google calendar for years. The doctor's appointment, the kids' football practice, the weekend side gig – all of it lives in Google and is invisible in work Outlook. The moment a colleague drops a meeting onto a seemingly free afternoon, a clean separation turns into a real scheduling clash.

Just as often it hits freelancers and consultants: the client provides a Microsoft 365 login inside their own tenant, while your own business runs on Google Workspace. If you don't reconcile the two, you juggle two separate availability pictures – and sooner or later book a client call over your own commitment. A two-way sync mirrors every booking into the other calendar instantly, no matter where you enter it.

And then the side projects: a club, a startup, a teaching role with its own Google calendar next to your Outlook main calendar. Here a single direction plus "busy only" is usually enough, so the main calendar treats the outside events as blockers – without any details spilling over.

🔐 Connection & security

How Outlook and Google connect

Both sides connect via OAuth 2.0 – we never store your password, only an encrypted token (ChaCha20-Poly1305). "Outlook" here covers Microsoft 365 Business, Outlook.com and Exchange Online; everything runs through a single Microsoft Graph endpoint, with no add-in or COM wrapper. Strict Microsoft tenants with a publisher-consent policy need a one-time tenant-admin consent (details at /en/it-admin/). On the Google side we request calendar scopes only – no mail, contacts or Drive permissions. Sync runs over both providers' push webhooks, typical latency seconds to a few minutes.

🧩 Native tools vs. Kalender Sync

Importing or adding Google Calendar to Outlook – and where the built-in tools end

Microsoft and Google only offer workarounds for bridging the two calendars. In Outlook you can add a Google calendar via "Subscribe from web" using its secret iCal address – but that subscription is strictly one-way and, on Outlook.com, often refreshes only every few hours up to a full day, so fresh events show up late or not at all. The other way round, you can subscribe to an Outlook iCal link inside Google – with the same lag and one-directional limitation. A manual .ics export and import, in turn, is just a snapshot: it copies every detail across once, unfiltered, and goes stale with the first change.

Kalender Sync replaces all that fiddling with a real connection over both providers' official APIs: two-way instead of one-way, seconds instead of hours, and with freely selectable detail depth instead of all-or-nothing. You decide per direction whether only "busy", title + time or full details arrive – and you never export manually or babysit a subscription again.