Time Zone Calculator

A time zone calculator takes a clock time in one place and tells you what the clock reads somewhere else at that same moment. Example: 2:00 PM in New York on September 15, 2026 is 11:00 AM in Los Angeles, 7:00 PM in London and 3:00 AM the next morning in Tokyo. Pick a date, a time and two zones; the converter applies daylight saving time for that exact date.

Three related tools on this site handle neighbouring questions. The Date and Time Calculator adds or subtracts hours and days from one moment; the Time Calculator adds and subtracts plain durations; and the Date Calculator counts days between calendar dates. This page is the one to use when the moment stays fixed and only the location changes.

The formula behind every conversion

Every time zone is defined by its offset from Coordinated Universal Time (UTC). The conversion is two subtractions and one addition:

The hour difference between two zones is simply offset B - offset A. The catch is that offsets are not constant: New York is UTC-5 in winter and UTC-4 in summer, London is UTC+0 in winter and UTC+1 in summer, and the switch dates differ by country. The calculator therefore looks up each zone's offset for the specific instant you entered rather than using a fixed table. Under the hood it uses the IANA time zone identifiers (America/New_York, Europe/London, Asia/Tokyo and so on) through the browser's Intl.DateTimeFormat API, which carries the full rule history for each zone.

Worked example: 2:00 PM Eastern to Pacific and Tokyo

Suppose a call is set for Tuesday, September 15, 2026 at 2:00 PM in New York. In September the East Coast is on Eastern Daylight Time, so offset A is UTC-4. Step one: 2:00 PM minus (-4 hours) gives 18:00 UTC. Step two for Los Angeles: Pacific Daylight Time is UTC-7, and 18:00 minus 7 hours is 11:00 AM PDT, same day, 3 hours behind New York. Step two for Tokyo: Japan Standard Time is UTC+9 all year, and 18:00 plus 9 hours is 27:00, which rolls over to 3:00 AM on Wednesday, September 16, 13 hours ahead of New York. The same instant is 7:00 PM in London (BST, UTC+1, 5 hours ahead), 8:00 PM in Berlin (CEST, UTC+2, 6 hours ahead), 11:30 PM in Mumbai (IST, UTC+5:30, 9 hours 30 minutes ahead) and 4:00 AM Wednesday in Sydney (AEST, UTC+10, 14 hours ahead).

How to use this time zone converter

1. Enter the date. It matters because daylight saving rules change the offset: 2:00 PM in New York is 4:00 AM in Sydney in September but 6:00 AM in January.
2. Enter the time as it reads on the clock in the source city.
3. Pick the source zone under "From time zone". Use the region tabs (US, Americas, Europe, Asia, Pacific) to find the city; the selected card is highlighted.
4. Pick the destination zone under "To time zone". The headline card shows the converted time, the zone abbreviation, the date, whether the day changed, and the hour difference.
5. Read the world table for the same moment in every listed city, sorted from west to east, with UTC offsets and a status dot for business hours.
6. Swap zones with one click to convert in the opposite direction.

The result updates instantly as you change any input, so you can step through several candidate meeting times without pressing a button.

Who this calculator is for

• Remote teams and freelancers scheduling calls between the US coasts, Europe and Asia.
• Travelers checking when to phone home, or what time a flight lands in local time.
• Sports and event fans converting a listed kickoff or launch time to their own clock.
• Customer support and sales staff making sure they call a client during that client's business hours.
• Students and researchers attending webinars or exams announced in another zone.
• Anyone confused by EST versus EDT who wants the difference on a specific date rather than a rule of thumb.

Key terms explained

• UTC: Coordinated Universal Time, the fixed reference from which all zones are measured. It never observes daylight saving time.
• UTC offset: how far a zone is ahead of (+) or behind (-) UTC, in hours and minutes. Eastern Standard Time is UTC-5; India is UTC+5:30.
• Standard time vs. daylight time: the winter and summer offsets of a zone. EST is UTC-5, EDT is UTC-4; PST is UTC-8, PDT is UTC-7.
• IANA zone identifier: the region/city name (for example America/Chicago) that software uses to look up a zone's complete rule set, including past and future DST changes.
• Zone abbreviation: the short label such as CDT or JST. Abbreviations are not unique worldwide (CST is used for both US Central Time and China Standard Time), which is why the calculator keys on city names instead.
• Day shift: whether the converted time falls on the same calendar day, the next day (+1) or the previous day (-1) compared with the source.

US time zones: standard and daylight offsets

Six of the seven US zones shift by one hour in summer. Arizona (outside the Navajo Nation) and Hawaii stay on standard time all year, which changes their difference from the rest of the country twice a year.

Read the last two columns as the answer to "what time is it there when it is 2:00 PM in New York?". Because the mainland zones move together, Chicago is always 1 hour behind, Denver 2 hours and Los Angeles 3 hours. Phoenix and Honolulu are the exceptions: Phoenix matches Denver in January and Los Angeles in September, and Honolulu is 5 hours behind New York in winter but 6 hours behind in summer.

2:00 PM Eastern around the world

This table shows the same 2:00 PM New York moment in major world cities on two dates: Tuesday, September 15, 2026 (US on daylight time) and Tuesday, January 12, 2027 (US on standard time). Notice how the difference to Europe stays put while the difference to Sydney and Auckland swings by 2 hours, because the southern hemisphere runs its daylight saving in the opposite season.

Daylight saving dates in 2026 and the windows where differences shift

The US, the UK and the EU, and Australia all change their clocks on different Sundays. The dates below are read from the IANA database for 2026; the right-hand columns show how the New York to London and New York to Sydney differences move through the year.

The practical lesson: a weekly New York to London call is an hour off for three weeks in March and one week in late October unless the invitation is anchored to one zone. A New York to Sydney call cannot keep the same local time in both cities at all, because the gap takes three values (14, 15 and 16 hours) across the year.

What changes the result

• The date. Only the date decides which offset applies. Move the same 2:00 PM Eastern from September to January and Sydney jumps from 4:00 AM to 6:00 AM.
• Whether a zone observes DST at all. Arizona, Hawaii, Japan, China, India, Singapore and most of Africa and South America keep one offset all year, so their difference from the US changes twice a year even though their own clocks never move.
• Hemisphere. Sydney, Melbourne and Auckland run daylight time from October to April, the mirror image of the US schedule, so their difference from the US swings by 2 hours rather than 1.
• Fractional offsets. India (UTC+5:30), Newfoundland (UTC-2:30), central Australia (UTC+9:30) and Nepal (UTC+5:45) produce half-hour and quarter-hour results.
• The direction of travel across the date line. Converting from Asia or Australia to the US often lands on the previous calendar day; converting from the US to Asia often lands on the next.

Second worked example: Friday 6:00 PM in Tokyo to the US

A product launch is streamed at 6:00 PM on Friday, September 18, 2026 in Tokyo. Tokyo is UTC+9, so the instant is 09:00 UTC on Friday. Subtract the US offsets in force in September: New York (UTC-4) sees it at 5:00 AM Friday, 13 hours behind Tokyo; Chicago (UTC-5) at 4:00 AM Friday; Los Angeles (UTC-7) at 2:00 AM Friday, 16 hours behind; and Honolulu (UTC-10) at 11:00 PM on Thursday, 19 hours behind and on the previous calendar day. The further west you go from Japan, the earlier the clock reads, until the day itself changes.

Tips for scheduling across zones

• Anchor the meeting to one named zone ("10:00 AM New York time"), not to an abbreviation like EST, which technically names only the winter offset.
• Use the world table's status dots to find an hour that is green (9 AM to 5 PM) or at least amber (7 AM to 10 PM) for everyone. A 9 AM to 5 PM day in New York covers 2:00 PM to 10:00 PM in London and 6:00 AM to 2:00 PM in Los Angeles, but only 10:00 PM to 6:00 AM in Tokyo.
• Re-check invitations in March, April, October and November, the months when one side of a call may have changed its clocks before the other.
• Write the date on both sides when a conversion crosses midnight. "3:00 AM Tokyo" is ambiguous unless you say "Wednesday".
• Prefer UTC for logs, servers and flight plans. Converting once to UTC and once back is safer than chaining zone-to-zone conversions.

Limitations and assumptions

• Results depend on the IANA time zone data installed in your browser and operating system; an outdated device may lag a recent rule change.
• The list covers 33 representative zones. Countries with several zones (Russia, Brazil, Australia, Canada, Mexico) are represented by their largest cities; a town in a different part of the country may use another offset.
• Times entered during a spring-forward gap (for example 2:30 AM in New York on March 8, 2026) do not exist on local clocks and are moved forward one hour; times in a fall-back overlap use the first occurrence.
• The business-hours status uses a fixed 9 AM to 5 PM window on every weekday and does not know about local holidays or weekends.
• Historical conversions before 1970 may be approximate in some browsers, which do not carry the full rule history.

When to use a sibling calculator instead

Use this page when the question is "what time is it there when it is X here". Use the Date and Time Calculator when the question is "what time will it be here in 36 hours", the Time Calculator when you are adding or subtracting plain durations such as 2:45 plus 1:20, the Date Calculator when the answer is a number of days between two dates, and the Hours Calculator when you need hours worked between a clock-in and a clock-out.

Sources

• U.S. Department of Transportation - Time Zones and Daylight Saving Time (the federal agency that administers US zone boundaries and DST under the Uniform Time Act and the Energy Policy Act of 2005).
• National Institute of Standards and Technology (NIST) - Daylight Saving Time rules and the official US time at time.gov.
• IANA - Time Zone Database (the source of every offset and transition date used by the calculator).