Timezone Converter
Compare one moment across multiple timezones, with DST handled correctly.
Timezone Converter tool
Offsets and daylight-saving status come from your browser's copy of the IANA timezone database, evaluated at the exact moment you chose — not at today's date.
What this tool does
Pick a zone and a moment in it, then add as many other zones as you like and read them all at once. Each row shows the local date and time, the UTC offset in force at that instant, the abbreviation the zone uses, and whether daylight saving is active. Rows that land on a different calendar day from the source are marked, which is the detail that ruins meeting invitations. The source zone defaults to the one your browser reports.
Common uses
- Finding an hour that works for people in three places, without doing arithmetic that is wrong twice a year.
- Working out what "09:00 Pacific" means for a release window you have to be awake for.
- Checking what a server in UTC will report when an event happens at a given local time.
- Reading a customer-reported incident time back into your own clock.
A short example
14:30 on 24 September 2026 in Berlin, viewed elsewhere:
Europe/Berlin 2026-09-24 14:30 +02:00 CEST DST
UTC 2026-09-24 12:30 +00:00 UTC
America/New_York 2026-09-24 08:30 -04:00 EDT DST
Asia/Kolkata 2026-09-24 18:00 +05:30 IST
Australia/Sydney 2026-09-24 22:30 +10:00 AESTNote Kolkata's half-hour offset and the fact that Sydney is not on daylight saving in September — the southern hemisphere's summer time runs from October to April.
Offsets, zones and the transitions in between
An IANA zone such as America/New_York is not a fixed offset. It is a rule set
covering the whole history of civil time in one place: New York has used −05:00 in winter
and −04:00 in summer since 1918, with wartime exceptions and a different transition date
before 2007. "The offset of New York" is only meaningful once you name the instant, which
is why this tool never shows an offset without a date attached.
Two local times a year are not ordinary. On the spring transition an hour never happens — 02:30 on the second Sunday in March does not exist in New York — and on the autumn transition an hour happens twice, so 01:30 is ambiguous without an offset. Enter a time in either case and the page says which and what it resolved to. Zones that shift by something other than an hour exist too: Lord Howe Island moves by thirty minutes.
Worth knowing
Abbreviations are not identifiers. "CST" is Central Standard Time in North America (−06:00), China Standard Time (+08:00) and Cuba Standard Time (−05:00), and there is no registry that resolves the conflict. Never store an abbreviation and never parse one — store an IANA name, or a UTC instant plus the offset that applied. The database itself changes several times a year as governments legislate; your browser ships a snapshot, so a very recent rule change may not be reflected until the browser updates.
Frequently asked questions
Why is the gap between London and New York sometimes four hours?
Because the two sides do not change on the same weekend. The United States moves on the second Sunday in March and the first Sunday in November; the UK and EU move on the last Sunday in March and the last Sunday in October. That leaves about three weeks each spring and one week each autumn when the usual five-hour difference is four — the weeks that quietly derail recurring invitations.
Does a timestamptz column store the timezone?
No, in spite of the name. PostgreSQL converts the input to UTC, stores eight bytes, and renders it through the session’s TimeZone setting on the way out, so two connections can read one row and print different clock times. Add a separate text column for the IANA name when the original zone carries meaning. Plain timestamp keeps the wall-clock reading and ignores zones altogether.
Why does my platform not recognise a zone name?
Because three naming systems are in circulation. The tz database keeps retired names as aliases in its backward file — Asia/Calcutta still resolves to Asia/Kolkata, US/Pacific to America/Los_Angeles — and a trimmed runtime built without that file rejects them. Windows uses its own labels such as Pacific Standard Time, which need the CLDR windowsZones table to translate into IANA identifiers.