How to schedule group meetings across Google Calendar and Outlook users
When you're coordinating an external group meeting, there's a reasonable chance your participants aren't all on the same calendar platform. One uses Google Calendar, another uses Outlook, a third has both. That shouldn't complicate the coordination — but it often does. Here's why, and what removes the friction entirely.
The mixed-calendar reality
In most external group meetings, participants are not using the same tools. One organisation runs on Google Workspace. Another is on Microsoft 365. A third is a smaller company where individuals have made their own choices. The meeting organiser rarely knows in advance which calendar system each participant uses, and it rarely matters — until they try to coordinate availability.
The challenge is not that Google Calendar and Outlook are incompatible. Both support standard calendar invite formats. Both can receive and display invites sent from the other platform. The challenge is the step before the invite — gathering everyone's availability when you have no visibility into any of their calendars.
What actually happens without the right tool
Without a tool that reads calendars directly, the organiser typically sends a polling request — a grid of time slots where participants indicate their availability. This works regardless of which calendar platform participants use, because it doesn't interact with the calendar at all. But it's also entirely manual. Every participant has to check their own calendar, cross-reference the options, make a selection, and submit.
The result is a completion problem. Some people fill it in immediately. Some fill it in after a reminder. Some never fill it in because the link sat in their inbox under twenty other things. The organiser ends up with partial data, has to chase the missing responses, and eventually makes a decision based on incomplete information.
There's a second problem that gets less attention: the data goes stale. A polling grid captures a snapshot of availability at the moment each person fills it in. By the time the last response arrives — especially after chasing — some of those earlier responses are no longer accurate. Calendars have changed. A meeting has been booked into a slot that looked free a week ago. The organiser makes their decision based on availability data that was correct when it was submitted, but may not be correct now. The result is a confirmation that lands on top of an existing commitment, another round of "sorry, that slot no longer works for me," and the whole process starts again from scratch.
The calendar platform each participant uses is irrelevant at this stage — the friction exists because the organiser can't see any of their calendars directly.
What changes when calendars are read directly
Whenn connects to both Google Calendar and Microsoft Outlook via their respective OAuth systems. Participants receive a personal link and connect whichever calendar they use — there's no restriction on platform, and the organiser doesn't need to know or specify which one in advance.
Once connected, Whenn reads free/busy data live from each participant's calendar at the moment AutoWhenn makes its decision — not from responses collected days or weeks earlier. A participant on Google Calendar and a participant on Outlook look identical to AutoWhenn — both are checked in real time against their actual current availability. The slot AutoWhenn selects is available for everyone right now, not just when they last looked at their calendar. That eliminates the gap between gathering availability and acting on it, which is exactly where the "sorry, that no longer works" problem lives.
The meeting confirms and sends invites automatically. Each participant receives an invite that lands correctly in their calendar — Google invite for Google users, Outlook invite for Outlook users — without any additional configuration from the organiser.
The mixed-calendar situation, which typically adds coordination complexity, stops being a factor entirely. The organiser adds participants by email and Whenn handles the rest regardless of what calendar system sits behind each address.
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Whenn handles the entire coordination process — automatically.
Add participants by email, they connect their calendar, AutoWhenn finds the best slot and sends everyone an invite.
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