Dates and Days

Time zone converter

What a time in one place is in another

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The same instant in a few places
PlaceLocal timeDateOffset
How this was counted
Converted time— Date there— Difference— From zone— To zone—

Your browser's own time zone database does the lookup; the daylight-saving gap and overlap are tested on every build. How it is checked

Pick a date, a time and two zones to see what that time is in the other place. The offset is computed for that date, so the answer is right in the few weeks each year when one side has moved its clocks and the other has not. The page also tells you when a time does not exist or happens twice.

Why the offset depends on the date

“New York is UTC-5” is true for about four months of the year; for the rest it is UTC-4. Most places that observe daylight saving work the same way, so “what is the offset of this zone” has no answer until you attach a date, and one stored number per zone is wrong for part of every year. This page asks the browser for the offset at the exact instant you entered.

The weeks when the usual gap is wrong

The United States moves its clocks in the second week of March and Europe in the last week of the same month. For the two or three weeks in between, New York and London are four hours apart, one hour less than the usual five, and every recurring meeting between them lands an hour out. In autumn the order reverses: Europe moves in late October and the US in early November, and the gap is four hours for the one week between. Southern-hemisphere zones shift in the opposite seasons, so an Australian meeting slot drifts twice a year against both.

Two hours a year: the skipped hour and the repeated one

When clocks go forward, an hour is deleted. On 8 March 2026 in New York the clock reads 01:59 and then 03:00, so a meeting invitation for 02:30 that morning refers to nothing. When clocks go back, an hour repeats: in New York, 01:30 on 1 November 2026 comes round twice, first on summer time and then an hour later on standard time. This converter names both cases, because in the first the time you were given is wrong and in the second it is incomplete.

Where the time zone data comes from

Governments change their clock rules several times a year, often with only weeks of notice. A copy of the database bundled into this page would be accurate on the day it shipped and would fall behind at the next change, with nothing on screen to show it. The converter reads the IANA database your browser already carries, which updates when the browser does. The page downloads no zone data of its own and sends nothing, and the answers are exactly as current as the browser giving them.

Questions

What time is 2pm New York in London?
Usually 7pm. New York and London are five hours apart for most of the year, but four hours apart for two or three weeks in March and one week around the end of October, because the two change their clocks on different dates. In those weeks 2pm in New York is 6pm in London. Pick the two zones above and the answer appears with the date there, which can differ from the date where you started.
Why does the gap between two cities change during the year?
Because daylight saving starts and ends on different dates in different places, and about two-thirds of the world's time zones do not observe it at all. The United States moves in March and November, Europe in late March and late October, Australia in October and April. For the weeks when one has changed and the other has not, the difference between them is an hour off its usual value. This page works out the offset for the date you give it, so those weeks come out right.
What happens if I pick a time that does not exist?
It tells you. As the clocks went forward in New York on 8 March 2026, the clock went straight from 01:59 to 03:00, so that day has no 02:30. This page says such a time does not exist in that zone and does not convert it, since a time in the gap means the time you were given was wrong.
What about the hour that happens twice?
It says that too. The clocks in New York go back on 1 November 2026, so 01:30 occurs twice that morning, once on summer time and once on standard time. They are two different instants an hour apart. This page converts one of them, flags the ambiguity and says whether it used the first or the second, so you know the answer depends on which one was meant.
Where does the time zone data come from?
Your own browser. Every browser ships the IANA time zone database and updates it along with the browser, and this page reads that copy. The rules change whenever a government decides to move or abolish daylight saving, so a copy built into a page would be right on the day it was built and out of date after the next change. Reading the platform's database keeps the answers as current as the browser is, and nothing is sent anywhere to get them.