Time Coordinator DST-aware meeting planning

Time Coordinator

Pick a date, set each participant's IANA time zone and working hours, and this page finds every shared window when everyone is available. It uses your browser's built-in time-zone engine, so daylight-saving changes are handled correctly for any date.

Private by design: everything is calculated locally in this tab. Zones, dates, and hours never leave your browser, and the schedule you copy is plain text generated on your device.

Plan a day

Overlap is calculated for this single day.

How the overlap is calculated

Every IANA time zone — such as Asia/Riyadh or America/New_York — is a named region with rules for its local time, including daylight-saving transitions. The page converts each zone's working window on your chosen date into UTC minute by minute, using the browser's Intl engine, then keeps only the minutes where every zone is in its window. The remaining contiguous blocks are your shared windows.

Because the conversion happens for the exact date you pick, the result automatically reflects whether a zone is on standard time or daylight saving time that day — and even handles the strange days when a local hour happens twice (fall back) or not at all (spring forward).

For example, someone in Riyadh (UTC+3) working 09:00–17:00 is available 06:00–14:00 UTC, while someone in New York working the same local hours is available 13:00–21:00 UTC in summer but 14:00–22:00 UTC in winter. The page shows you the actual intersection for the date you choose.

Privacy and limitations

Privacy. This page makes no network requests. Dates, zones, and working hours are processed entirely in your browser, and the copied schedule is generated locally. There is no account, no telemetry, and no server.

Limitations. This prototype plans a single date with same-day working windows — overnight shifts that cross midnight are not supported yet. Working hours are minute-accurate but the copyable schedule shows hours and minutes, not holidays, shifts, or personal calendars. Zones come from a curated IANA list; if you need a zone that is missing, note it and a free-text zone field can be added. Fairness rotation, share links, and calendar (.ics) export are planned for a later version.