Time Zone Overlap Calculator

The calculator converts the working hours you define for Location 1 into UTC, then does the same for Location 2 (and optionally Location 3). It finds the intersection of all those UTC windows — the period when every location is simultaneously within working hours — and reports that as the overlap window.

Zero overlap means there is no single hour of the day where all selected locations are within their standard working hours at the same time. This is common between locations like New York and Singapore. In this case, teams typically need to agree on an early-morning or late-evening meeting outside normal hours for at least one party.

The current tool supports up to three time zones simultaneously. For larger distributed teams, you can run multiple comparisons — for example, find the overlap between Zone 1 and Zone 2 first, then check whether Zone 3 falls within that window.

UTC offsets provide a stable, unambiguous reference regardless of daylight saving time (DST) changes. City-based time zones shift by one hour during DST transitions, so the offset you select should reflect the current or target offset for each location. Check your region's current UTC offset before using the tool during DST periods.

Most remote work experts recommend at least 2–4 hours of daily overlap for effective collaboration. This window allows for real-time communication, standups, and decision-making. Fewer than 2 hours often makes synchronous collaboration difficult and requires heavy reliance on asynchronous communication.

Daylight saving time shifts the UTC offset for affected regions, typically by +1 hour in summer. When using this calculator during DST periods, select the adjusted UTC offset for each location — for example, New York shifts from UTC−5 (EST) to UTC−4 (EDT) in summer. Always verify the current offset for each region.

Yes. The overlap window shown is the ideal recurring slot — any time within that window works for all locations on any standard workday. Just verify that local holidays or seasonal DST changes don't shift the window before scheduling recurring events far in advance.

This calculator assumes a single continuous work block for each location defined by Location 1's start and end times offset across zones. If your team uses split shifts or highly flexible hours, you can run the calculator multiple times with different start/end windows to find all possible overlap slots throughout the day.