Time Zone Converter & Meeting Planner
Convert a date and time from one IANA zone to many at once — DST-aware, with offsets and day changes shown — and find the hours that suit everyone.
A table of the same moment on every colleague’s clock, a UTC anchor for the invite, and the list of hours when everyone is inside the working window you set.
Example: 14:00 on 19 Sep 2026 in Asia/Jakarta is 08:00 in London (+01:00), 03:00 in New York (−04:00), 17:00 in Sydney; with a 9–17 window Jakarta and London share 15:00 and 16:00 Jakarta time.
One instant,
every clock.
Where the zone data comes from, how a wall-clock time becomes an instant, and how the overlap hours are found.
Zones and offsets
Zones are IANA names — Europe/London, America/New_York, Asia/Jakarta — and their offsets come from the time-zone database built into your browser's Intl implementation, evaluated at the instant in question, so daylight-saving changes are applied per date rather than as a fixed offset. Abbreviations like EST or CET are not accepted because they are ambiguous; the page tells you which names it could not resolve.
From wall clock to instant
A local date and time in the source zone is turned into a UTC instant by guessing that the wall time is UTC, asking the zone for its offset at that guess, correcting, and repeating until stable — which also settles the two edge cases around a daylight-saving change (a time that does not exist, or one that happens twice). The instant is then rendered in every target zone, with its offset and a day-shift marker when the calendar date differs from the source.
Finding a meeting hour
The working window (prefilled 09:00–17:00, yours to change) is applied to every zone alike. For each whole hour of the source day the page converts that hour to each zone and counts how many fall inside the window; hours where all do are the candidates. It does not know weekends, holidays or individual calendars — check the weekday column. Nothing leaves the browser; the same four anonymous usage counts as the rest of the site apply.
SOURCES
- IANA Time Zone Database (as shipped in the browser’s Intl implementation) — zone names, offsets and daylight-saving rules
- ECMA-402 Intl.DateTimeFormat — timeZone and formatToParts used for the conversions
Last reviewed 19 September 2026. How results are checked: How we verify.