Meeting Time Overlap Calculator
Meeting Time Overlap Calculator two timezone work hours overlap shared meeting window finder remote team availability comparisonCompare two local availability windows
Choose the meeting date, each person’s named time zone, and their same-day local start and end times. Every zone name includes its effective UTC offset for that date. Select Find overlap to see the shared duration in UTC and both local times.
How overlap is found
The browser converts each local start and end through the selected IANA time zone for the chosen date. The later of the two UTC starts becomes the possible meeting start; the earlier UTC end becomes the finish. When the finish is after the start, that interval is available to both people.
Worked example
On January 15, a person in Chicago is free 9:00 AM–5:00 PM CST, equal to 15:00–23:00 UTC. A person in London is free 9:00 AM–5:00 PM GMT, equal to 09:00–17:00 UTC. Their overlap is 15:00–17:00 UTC: 9:00–11:00 AM in Chicago and 3:00–5:00 PM in London, lasting two hours.
Why the date matters
A named zone carries regional daylight-saving rules, while a bare UTC offset does not. Chicago may be UTC−6 in winter and UTC−5 in summer; London may be UTC+0 or UTC+1. The dropdown recalculates its displayed offsets when the meeting date changes, removing that lookup from the visitor’s task.
Choosing a time zone
The first person defaults to the browser’s current named zone when the browser reports one. Lists use standard IANA names, with familiar regional labels added for common zones. Type the first letters while the dropdown is focused to jump through its native options. UTC remains available for teams that schedule directly in coordinated time.
Assumptions and limitations
Each availability interval must start and end on the same local calendar day, with end later than start. Overnight windows are outside this tool’s scope. Results rely on time-zone data bundled with the browser and do not schedule meetings, read calendars, account for holidays, compare more than two people, or guarantee how another calendar interprets an ambiguous clock time during a daylight-saving transition.
Using the window fairly
A mathematical overlap is not automatically a good recurring meeting time. Consider lunch, caregiving, accessibility, and how early or late the interval feels locally. For a rotating international team, share inconvenient slots instead of assigning the same burden every week. Confirm the final date and local times in calendar invitations.
Meeting Overlap FAQ
Do I need to know my UTC offset?
No. Choose a named time zone; the matching date-aware offset appears beside it.
Why are city or region names used?
Abbreviations such as CST can mean different zones. IANA region names identify the rule set the browser should apply.
Does touching at one endpoint count?
No. If one window ends exactly when the other begins, there is zero shared meeting time.