This calculator converts your acceptable working hours (default 8 AM to 7 PM local) into UTC, finds the overlapping window across all time zones, and reports every time slot that works for everyone. If no overlap exists, it tells you so — and suggests the smallest expansion (one person starting at 7 AM, or another staying until 8 PM) that creates a workable window.
Why most cross-time-zone meetings are scheduled badly
Most teams default to the organizer's local time, which often means one team joins at 6 AM or 11 PM. The result: low engagement, resentment, and "I'll catch the recording" responses. A better practice is to identify the natural overlap window and stick to it — or rotate the inconvenience so different time zones take turns being inconvenienced.
Best practices for async-first teams
If you cannot find a humane overlap, go async: record a Loom video, write a Slack summary, and use a shared doc for decisions. Async-first teams typically run only one synchronous meeting per week (the "all-hands") and handle everything else through writing. This is how Gitlab, Automattic, and other fully-remote companies operate across 30+ time zones.
Daylight Saving Time warning
DST changes happen on different dates in different regions (U.S. shifts in March/November; Europe shifts on different dates; most of Asia and Australia do not observe DST). A 9 AM meeting that works in February may break in March when the U.S. shifts but Europe has not. Recurring cross-zone meetings should be reviewed twice a year.