Time zone overlap finder
Find the hours when everyone across a list of time zones is in working hours.
Time zone overlap finder
Paste a list of time zones — one per line, as an IANA name like Europe/Bratislava or a city like Tokyo — and this tool works out exactly which hours everyone is inside their working day. It is built for distributed teams deciding when to schedule a call, on-call rotations spanning continents, and anyone coordinating with people who wake up and sign off at different points in the same 24 hours.
Working hours default to 9–17 for every zone, but a single line can override it: add "9-17" after the zone name (for example "America/New_York 9-17") when one team keeps different hours than the rest. The minimum overlap length filters out gaps too short to be useful — set it to two or three hours if a quick sync needs more than a few overlapping minutes. A specific date matters because UTC offsets shift with daylight saving: a pair of zones that overlap for seven hours in January can overlap for only five in July, so pick the date the meeting will actually happen on.
Choose between two views. The 24-hour grid marks every zone's working hours against a UTC axis, with a final row showing exactly where all of them line up — useful for eyeballing a whole day at once. The list view instead prints each qualifying window as a ready-to-read line per zone, in 12- or 24-hour format, which is the faster read when you already know roughly when to meet and just need the exact local times to put in an invite.
Everything runs in your browser: the zones and working hours you enter are never uploaded anywhere. Copy the result, download it as a .txt file, or send it to another tool's input to keep working on it.