Time zone converter

Enter the time someone gave you and the zone they wrote it in. You get it in every US time zone and around the world for that exact date — including whether “EST” actually meant EDT that week.

Converted time

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Original—
Difference—
UTC—
Your device—
ISO 8601—

The same moment, everywhere at once

Every row is the identical instant, written in local clock time.

Whose working day does it land in?

Each column is one hour of the chosen day. Tap any square to move the meeting to that hour.

9am–6pm localearly or late, still workablemiddle of the night

The nine US time zones

ZoneStandardDaylightWhere
AtlanticAST, UTC−4no changePuerto Rico, US Virgin Islands
EasternEST, UTC−5EDT, UTC−4New York, Atlanta, Miami, Boston, Detroit, most of Indiana
CentralCST, UTC−6CDT, UTC−5Chicago, Dallas, Houston, Nashville, Minneapolis, New Orleans
MountainMST, UTC−7MDT, UTC−6Denver, Salt Lake City, Albuquerque — and Arizona, which never changes
PacificPST, UTC−8PDT, UTC−7Los Angeles, San Francisco, Seattle, Las Vegas, Portland
AlaskaAKST, UTC−9AKDT, UTC−8Anchorage, Juneau, Fairbanks
Hawaii–AleutianHST, UTC−10HDT in the Aleutians onlyHawaii never changes; Adak does
SamoaSST, UTC−11no changeAmerican Samoa
ChamorroChST, UTC+10no changeGuam, Northern Mariana Islands

Arizona sits in the Mountain zone but does not observe daylight saving, so for half the year Phoenix matches California rather than Denver. The Navajo Nation, which crosses into Arizona, does observe it.

When the clocks change

RegionForwardBackRule
United States & Canada8 Mar 2026
14 Mar 2027		1 Nov 2026
7 Nov 2027		2nd Sunday in March → 1st Sunday in November, at 2am local
UK, Ireland & EU29 Mar 2026
28 Mar 2027		25 Oct 2026
31 Oct 2027		Last Sunday in March → last Sunday in October, at 01:00 UTC
Australia (NSW, Vic, SA, Tas)4 Oct 2026
3 Oct 2027		5 Apr 2026
4 Apr 2027		1st Sunday in October → 1st Sunday in April
New Zealand27 Sep 2026
26 Sep 2027		5 Apr 2026
4 Apr 2027		Last Sunday in September → 1st Sunday in April

For three weeks each spring and one week each autumn, the US and Europe are out of step: London is normally five hours ahead of New York, but briefly four. Queensland, Western Australia, the Northern Territory, most of Asia, Africa and South America do not change clocks at all.

Abbreviations that collide

LettersCould mean
CSTUS Central Standard, UTC−6 — or China Standard, UTC+8 — or Cuba Standard, UTC−5
ISTIndia Standard, UTC+5:30 — or Irish Standard, UTC+1 — or Israel Standard, UTC+2
BSTBritish Summer, UTC+1 — or Bangladesh Standard, UTC+6
AMT, WST, ECTSeveral conflicting meanings each; avoid entirely

This is why the converter is built on city names and the IANA zone identifiers behind them. America/New_York is unambiguous in a way that “EST” is not.

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The one-hour mistake almost everyone makes

Someone writes “10 PM EST” in July. Strictly, EST does not exist in July — the eastern United States is on EDT then, an hour ahead at UTC−4. Read the message literally and you arrive an hour late. Read what they meant and you arrive on time. Nearly everyone means Eastern local time whatever the season, so this page follows local time by default and tells you plainly which abbreviation is really in force on the date you picked. If you genuinely need strict, never-shifting EST, it is in the list under fixed offsets, kept deliberately separate.

10:00 PM Eastern · 2 Sep = 9:00 PM Central · same day · 02:00 UTC the next morning

Why the gap between two cities is not a constant

London is five hours ahead of New York for most of the year, four hours ahead for about three weeks in March, and five again from late October. The two regions change their clocks on different Sundays, so any rule you memorise is wrong several weeks a year. Sydney is worse: it moves in the opposite direction, so the gap to Los Angeles swings across a four-hour range. The only reliable method is to resolve the offset for the specific calendar date, which is what happens here — not for today, for the date in the field.

Twice a year a clock time is a trick question

On the spring-forward Sunday, clocks jump from 2:00 to 3:00 and 2:30 AM simply never happens. On the autumn Sunday, 1:30 AM happens twice, an hour apart, and the two are different instants that convert to different times everywhere else. Most converters answer these silently and confidently, and one of the two answers is wrong. This one flags both cases and tells you which instant it chose, so you can go back and ask.

How the arithmetic is done

Every browser ships the IANA time zone database, the same dataset used by Linux, macOS and most servers, covering every zone rule change back to 1970 and scheduled changes going forward. The page asks the browser for the exact offset in force at the instant you specified, then reverses the calculation to find the single moment in absolute time your wall clock refers to, then re-expresses that moment in every other zone. Nothing is approximated, no table of offsets is hardcoded, and nothing is sent to a server — the entire conversion runs on your device. If your operating system is current, so is the zone data.

Writing a time that cannot be misread

The safest form names a city or a UTC offset alongside the abbreviation: “Thu 3 Sep, 10:00 PM New York (UTC−4)”. Better still, send a UTC time and let each calendar render it. Calendar applications handle the standard-to-daylight switch correctly when you pick a named zone such as Eastern Time rather than typing letters into the subject line; almost every scheduling error traces back to a time that was written as prose instead of stored as a zone.

Frequently asked questions

I was told 10 PM EST — what time is that in CST?
9 PM Central, on the same date. Central is always one hour behind Eastern, whether both are on standard time or both on daylight time. The catch is the date: if it falls between the second Sunday in March and the first Sunday in November, the eastern US is actually on EDT, so “10 PM EST” written then almost certainly meant 10 PM Eastern local time.
Is EST the same as Eastern Time?
No. Eastern Time is the zone; EST and EDT are the two offsets it uses. EST is UTC−5 in winter, EDT is UTC−4 in summer. People write EST year-round out of habit, which is harmless in conversation and costly in a calendar invite.
How many time zones does the United States have?
Nine, counting the territories: Atlantic, Eastern, Central, Mountain, Pacific, Alaska, Hawaii–Aleutian, Samoa and Chamorro. Six of those cover the states, and only the first five of the six change their clocks.
Which parts of the US never change their clocks?
Arizona outside the Navajo Nation, Hawaii, Puerto Rico, the US Virgin Islands, Guam, the Northern Mariana Islands and American Samoa. That means Phoenix matches Denver in winter and Los Angeles in summer, without moving at all.
What happens if I schedule a meeting at 2:30 AM on the day clocks go forward?
That clock time does not exist — the hour is skipped. Most systems silently shift it forward to 3:30 AM. This converter tells you when you have hit that gap, and likewise when a time falls in the repeated hour each autumn and could mean either of two instants.
Why does the time difference between two cities change during the year?
Because regions start and end daylight saving on different dates, and some never do. London is five hours ahead of New York most of the year but four for roughly three weeks each March. Any offset you memorise will be wrong for part of the year, which is why the date matters as much as the time.

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Guides & articles

conversionEST vs EDT: The One-Hour Mistake Almost Everyone Makes6 min read