How to Sync Outlook and Google Calendar (4 Ways, 2026)
Two calendars that can’t see each other is how you end up double-booked. There are four ways to connect Outlook and Google Calendar, and they differ enormously in how fast they update and how much they reveal.
Start with what you’re actually trying to achieve, because it decides the method. Seeing your own events in one place is a different problem from making sure a coworker can’t book over your dentist appointment.
1. Subscribe to an ICS feed (free, built in)
Both platforms can publish a calendar as an iCalendar (ICS) URL and both can subscribe to one. This is the no-cost, no-software route.
Google Calendar into Outlook
- Open Google Calendar on the web
- Click the gear icon and choose Settings
- Under Settings for my calendars, click the calendar you want to share
- Scroll to Integrate calendar
- Copy the Secret address in iCal format
- Go to Outlook, open Calendar, and click Add calendar
- Choose Subscribe from web
- Paste the URL, give the calendar a name and color, and click Import
Outlook into Google Calendar
- In Outlook on the web, click the gear icon and open Calendar
- Choose Shared calendars
- Under Publish a calendar, pick the calendar and a permission level
- Select Can view all details or a more limited option, then click Publish
- Copy the ICS link (not the HTML one)
- In Google Calendar, click the + next to Other calendars
- Choose From URL, paste the link, and click Add calendar
Do both directions and each calendar shows the other’s events.
What to know before relying on it. Subscribed feeds are read-only and refresh on the receiving provider’s schedule rather than instantly. Google’s refresh for external ICS feeds is commonly measured in hours, which means a meeting you accept this morning can stay invisible on the other calendar for most of the day. That is fine for a stable schedule and genuinely dangerous for a fast-moving one.
The secret ICS address is also exactly what it sounds like. Anyone who obtains that URL can read the calendar without signing in, so treat it like a password and regenerate it if it leaks.
2. Share directly inside one organization
If both accounts are yours and both live in the same Microsoft 365 tenant or the same Google Workspace domain, skip the feeds. Native sharing inside a single tenant updates immediately and respects permissions properly.
In Google Calendar, that’s Settings for my calendars, then Share with specific people or groups. In Outlook, it’s Share on the calendar, then entering the address and choosing a permission level.
This only works within one provider’s ecosystem. It does not bridge Google and Microsoft.
3. Use a calendar sync tool (the fix for speed and privacy)
Feeds and sharing both fail on the same two points: they lag, and they show your actual event titles to whoever can see the calendar. A sync tool solves both by copying events across and rewriting them on the way.
Carly Calendar Sync does this for free with no signup required to try it. You pick a source calendar and a destination, and it watches the source for new, updated, and deleted events and mirrors them onto the destination. The source is never modified.
The useful part is the rule layer. Before an event copies, you decide what carries over:
- Match on title, description, location, organizer, duration, attendee count, hour of day, day of week, weekday versus weekend, all-day versus timed, or visibility
- Set on the copy the title (literally or from a template), description, location, whether attendees are kept or stripped, and whether it lands as Busy, Free, or Tentative regardless of the source
- Decide the remainder, so non-matching events either don’t copy at all or mirror through untouched
A single rule such as “if visibility is private, copy as Busy with attendees stripped” gives you the common outcome: personal appointments become anonymous blocked time on the work calendar, while work meetings keep their real names. A live preview re-runs as you edit, so you can see what would leak before connecting anything.
Paid tools in this category price by the number of calendars you connect, which is worth checking against how many accounts you actually juggle.
4. Build it yourself with an automation tool
Zapier, Make, or a script against the Google Calendar and Microsoft Graph APIs can watch one calendar and create matching events on the other, with your own filters in between.
This is the most flexible option and the most work. The hard parts are not the happy path: they’re updates, deletions, recurring series, all-day events crossing time zones, and avoiding loops when the mirrored event triggers the sync back the other way. A dedicated tool has already handled those.
Reach for this when calendar sync is one step inside a longer workflow you’re building anyway. Carly’s free workflow steps cover this shape of automation, with AI agents from $35/month when a step needs judgment rather than rules.
Which method to pick
You just want to see everything in one app. ICS subscription is fine. The lag doesn’t matter because you’re the only consumer and you already know what you scheduled.
Coworkers book over your other commitments. You need mirroring, not subscribing, because you need busy blocks on the calendar they look at, and you need them to appear promptly.
The event details are sensitive. Rule out plain sharing and ICS entirely, since both carry real titles. Use a tool that rewrites events as they copy.
Everything is in one Google or Microsoft tenant. Use native sharing and stop there.
FAQ
Can I sync Outlook and Google Calendar two ways for free?
Yes. Publish each calendar as an ICS feed and subscribe to it from the other platform, which costs nothing but is read-only and refreshes on a delay. For near real time two-way mirroring with control over what details cross over, Carly Calendar Sync is free as well.
Why is my synced calendar not updating?
Subscribed ICS feeds refresh on the receiving provider’s schedule rather than on demand, and for external feeds that interval is typically hours. There’s no supported way to force a refresh, which is the main reason people move to a sync tool.
Does syncing show my private event details?
With ICS feeds and direct calendar sharing, yes, unless you chose a limited permission level when publishing. Anyone who can see the calendar sees the titles. A rule-based sync tool lets you replace titles with “Busy” and strip attendees on the events you choose.
Is the secret ICS address safe to share?
No. It grants read access to that calendar to anyone holding the link, with no sign-in. Only paste it into a service you trust, and regenerate it from Google Calendar settings if you think it has been exposed.
Will syncing create duplicate events?
It can, if you set up mirroring in both directions without rules that exclude already-copied events. Sync one direction per pair of calendars, or use a tool that marks and recognizes the events it created.
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