Sync Outlook and Google Calendar: 3 Methods Compared
You use Outlook at work and Google Calendar personally — or the other way around. Events collide because neither calendar knows what’s happening in the other. This can be fixed, but not every approach is equally good.
At a Glance
| iCal subscription | gSyncit | Kalender-Sync | |
|---|---|---|---|
| Direction | One-way | Two-way | Two-way |
| Speed | Up to 24h | Minutes | Real-time |
| Event details visible | Yes | Yes | No |
| GDPR-compliant | Partially | Partially | Yes |
| Price | Free | $0-40/mo. | Free |
Recommendation: If you only want to sync availability and need to comply with GDPR: Kalender-Sync. Setup in under 5 minutes, no Outlook add-in, no admin required.
Here are all three approaches in detail, honestly assessed.
Method 1: iCal Subscription (Free, but Limited)
Outlook can export a calendar as an iCal link. You subscribe to this link in Google Calendar — or vice versa.
How to do it:
- In Outlook: Calendar > Right-click > “Publish to internet” > Copy link
- In Google Calendar: “Other calendars” > “From URL” > Paste link
Pros:
- Free
- No additional software
Cons:
- One direction only (Outlook to Google OR Google to Outlook, not both)
- Updates take up to 24 hours — Google polls infrequently
- Events are fully visible (titles, attendees, notes)
- Changes and deletions often don’t come through at all
For a quick overview of “what’s on next week,” this works. For reliable synchronization, it doesn’t.
Method 2: Third-Party Tools (gSyncit, SyncGene & Co.)
Tools like gSyncit (Outlook plugin), SyncGene, or CalendarBridge synchronize events fully between Outlook and Google.
gSyncit is an Outlook add-in that runs directly in the desktop app. It copies events bidirectionally — including all details.
Pros:
- True two-way synchronization
- Also works with contacts and tasks (gSyncit)
Cons:
- gSyncit only runs on Windows with Outlook Desktop — no Mac, no Outlook Web
- Complete event content is copied — problematic for confidential meetings
- Many of these tools host on US servers
- IT departments must approve Outlook add-ins, which takes time in regulated environments
- gSyncit free version only syncs 1 calendar with a delay
Who this works for: individuals on Windows who deliberately want to copy full events between two personal accounts and don’t have a GDPR concern.
Method 3: Free/Busy Sync with Kalender-Sync
Instead of copying complete events, Kalender-Sync only syncs whether a slot is free or busy. In the target calendar, a “Blocked” entry appears — without title, attendees, or notes.
Step by step:
- Sign up at kalender-sync.de — choose your calendar and provider, done.
- Connect Outlook — sign in with your Microsoft 365 account. Kalender-Sync only requests the minimum required calendar permissions.
- Connect Google Calendar — OAuth sign-in, select calendar, done.
- Create a sync rule — define: Outlook to Google, Google to Outlook, or two-way. Only free/busy data flows.
- Choose time range — how many days ahead to sync? Include or exclude all-day events? You decide.
- Activate — one click. Changes are picked up in real-time via webhook.
- Verify — the audit log transparently shows which entries were synced.
Setup time: under 5 minutes. No Outlook add-in, no admin required.
Pros:
- True two-way synchronization
- No event content is transferred
- Hosted in Germany (Hetzner), DPA available
- Works with Outlook Web, Desktop, and Mobile
- Currently available for free
Cons:
- No event copying (if you need that, this is the wrong approach)
- Still growing — feature set is expanding
Add Google Calendar to Outlook
Viewing your Google Calendar in Outlook — that works without a sync tool too. In Google Calendar: Settings > Calendar > “Secret address in iCal format” > copy. In Outlook Web: “Add calendar” > “Subscribe from web” > paste link.
The problem: one-way only (Google to Outlook), up to 24 hours delay, and all event details are visible. If you only need availability and must comply with GDPR, Kalender-Sync is the better option.
Note: Whether you use a personal Gmail account or Google Workspace with a custom domain — the synchronization works identically.
Comparison at a Glance
| iCal subscription | gSyncit / SyncGene | Kalender-Sync | |
|---|---|---|---|
| Direction | One-way | Two-way | Two-way |
| Speed | Up to 24h | Minutes | Real-time (webhook) |
| Event content visible | Yes | Yes | No (free/busy only) |
| Hosting | Local / Google | Local / US | Germany |
| Price | Free | $0-40/month | Free |
| Admin/IT required | No | Often yes (add-in) | No |
| GDPR-suitable | Partially | Partially | Yes |
Common Problems and Solutions
Duplicate entries: Check if you accidentally have multiple sync rules or an iCal subscription running in parallel.
Timezone issues: Make sure Outlook and Google use the same timezone. Outlook Web and Desktop can have different settings.
Permission errors: OAuth tokens expire. In Kalender-Sync, you can re-establish the connection under Settings.
Outlook add-in blocked: Many companies centrally block add-ins. Kalender-Sync doesn’t need an add-in — it connects directly via the Microsoft API using OAuth.
Frequently Asked Questions
- Can I sync Outlook and Google Calendar for free? Yes — iCal feeds are free (but one-way and slow). Kalender-Sync is currently available for free with full functionality.
- Does the sync work with Outlook Web and the desktop app? Yes. Kalender-Sync connects via the Microsoft API, not via an add-in. Whether you use Outlook Web, Desktop (Windows/Mac), or the mobile app — blockers appear everywhere.
- Do I need an admin or the IT department? No. You can set up the OAuth connection yourself. No Outlook add-in needs to be installed or approved by IT.
- What’s the difference between gSyncit and Kalender-Sync? gSyncit copies complete events (title, attendees, notes) and only runs on Windows. Kalender-Sync only transfers availability (free/busy), works on all platforms, and is GDPR-compliant.
- Are deleted events also synced? Yes. If you delete an event in Outlook, the corresponding blocker in Google is automatically removed — and vice versa.
- Can I sync Outlook with Google Tasks? No, Kalender-Sync exclusively syncs calendar events, not tasks or contacts.
Which Method Is Right for You?
- Quick overview, no effort: iCal subscription
- Full event copy, Windows only, no GDPR concern: gSyncit
- Sync availability, GDPR-compliant, all platforms: Kalender-Sync
Sync Outlook & Google Calendar now — available for free
