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Timezone Converter

Convert times between timezones instantly. Supports 28+ world timezones with DST handling.

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Pick a date above - conversions will appear here once you enter one.

How to Use the Timezone Converter

  1. Pick a source timezone from the first dropdown. Each option shows the IANA identifier (for example America/New_York) followed by the current UTC offset (like GMT-5) - offsets shift with DST, so what you see today may not match six months from now.
  2. Enter a date and a time in the two fields. The date defaults to today; the time defaults to 12:00.
  3. Manage target timezones: the tool starts with New York, London, and Tokyo. Use the "Add a target timezone" dropdown to append others, and the Remove button on each row to drop one.
  4. Read the converted times. Each target row shows the weekday, full date, and 12-hour clock representation of that exact instant expressed in the target zone.

What The Converter Is Actually Doing

This is a pairwise lookup, not a dashboard - you pick a moment in one zone and the tool tells you what a clock reads in every target zone at that same instant. Internally it first builds a "fake UTC" Date from your inputs, then uses Intl.DateTimeFormat with timeZoneName: 'longOffset' to ask the browser what the real offset of the source zone is on that specific date. That offset is subtracted to get a true UTC instant, and then the same instant is re-formatted for each target zone with Intl.DateTimeFormat({ timeZone: target }). The two-step dance is necessary because HTML's <input type="date"> and <input type="time"> give you wall-clock components with no attached zone; you have to choose the zone yourself and translate.

Concrete Reasons To Convert

  • Scheduling a one-off Zoom or Google Meet with a client in another region and confirming what "3 PM Tuesday your time" means for you.
  • Posting a product launch announcement where the timestamp needs to read sensibly in every target market.
  • Planning a cron job or scheduled deploy that fires at low traffic in Asia while the on-call engineer is awake in Europe.
  • Interpreting a historical log timestamp where the incident write-up is in UTC and leadership wants to know what time the users saw it.
  • Figuring out a flight landing time when the ticket lists departure in origin local and arrival in destination local.
  • Confirming the cutoff for an exchange, auction, or tax-filing deadline that is stated in a zone you do not live in.

Where Timezone Conversion Quietly Lies To You

  • DST transition windows. On "spring forward" day the 2:00-3:00 AM hour simply does not exist; on "fall back" day 1:00-2:00 AM happens twice. A meeting scheduled at 2:30 AM on the first is undefined; one scheduled at 1:30 AM on the second is ambiguous. The IANA database handles both, but only if the source has a real offset - not a loose "EST" abbreviation.
  • Fractional-hour offsets. India is UTC+5:30, Nepal is UTC+5:45, Iran is UTC+3:30, the Chatham Islands are UTC+12:45. "Add 5 hours" will silently produce the wrong time in any of these.
  • Offset abbreviations collide. "CST" means Central Standard Time (US, UTC-6), China Standard Time (UTC+8), or Cuba Standard Time (UTC-5) depending on context. "IST" means Indian, Israel, or Irish Standard Time. The IANA identifiers (America/Chicago, Asia/Shanghai, America/Havana) are unambiguous; abbreviations are not.
  • Political changes. Samoa jumped the International Date Line in December 2011. Turkey stopped observing DST in 2016. North Korea briefly used UTC+8:30. The Olson database tracks all of this; a hand-rolled offset table does not.
  • DST ending dates drift by country. The US and EU no longer change on the same Sunday. Mexico abolished DST in 2022. Always rely on the IANA zone, not a hard-coded offset.

The IANA TZ Database in One Paragraph

The IANA Time Zone Database (also called the tz database or Olson database after founder Arthur David Olson) is the canonical record of civil timezones on Earth. It is bundled into every modern OS and every JavaScript engine via ICU. Zone identifiers follow the Continent/City pattern, with the city chosen for historical stability - America/New_York covers most of the US East Coast. Release cadence is roughly quarterly, tagged like 2024a, 2024b. When a government announces a DST change on short notice (Chile, Lebanon, and Jordan have all done this), a new tzdata release ships to operating systems within weeks.

This Page vs. Calendar Apps, Worldtimebuddy, and Shell Tools

Worldtimebuddy is a beloved dashboard for recurring meeting planning, with a horizontal time slider and saved city sets; it beats this page for repeated team scheduling. Google Calendar and Outlook auto-convert event times as you scroll between zones - if the meeting is actually being booked, use the calendar. Shell tools like TZ=Asia/Tokyo date on Linux/macOS give you the current time in any zone in one line, and date -d "2024-05-15 14:00 America/New_York" -u does the conversion math from the terminal. This page wins when you want a visual side-by-side of one specific moment across several zones, without opening a calendar or a terminal. If you want the always-running many-city dashboard, use our World Clock instead - that is the tool for the second use case.

Frequently Asked Questions

Why does the dropdown show GMT instead of UTC?

The browser Intl API reports short offsets as "GMT-5," "GMT+9," and so on. GMT (Greenwich Mean Time) and UTC are within a second of each other for civil purposes - the difference is that UTC is defined by atomic clocks with leap-second insertions while GMT is defined by Earth rotation. Browsers use GMT as the display prefix for historical reasons (it was adopted first). Internally, though, the math is always UTC-based, and toISOString() emits the Z suffix for UTC.

Does it account for daylight saving time on the specific date I entered?

Yes. The conversion asks the browser Intl API for the real UTC offset of the source zone on the exact date you entered, not the offset as of "right now." So if you enter January 15 for New York, it uses EST (UTC-5); if you enter July 15, it uses EDT (UTC-4). The same applies to each target zone. DST rules for past dates reflect what the law was at the time, so a 1985 timestamp uses 1985-era rules.

Why does the list stop at 28 timezones?

It is a curated list covering North America, South America, Europe, Africa, Middle East, South Asia, East Asia, and Oceania. The full IANA database has over 340 identifiers, many covering territory-specific exceptions (America/Kentucky/Monticello, Europe/Busingen). For a niche zone, convert from a nearby major city with the same offset and DST rules.

How does it handle countries with half-hour or 45-minute offsets?

Correctly, because the calculation pulls the actual offset from Intl.DateTimeFormat rather than assuming whole-hour arithmetic. India (UTC+5:30), Iran (UTC+3:30), Afghanistan (UTC+4:30), Nepal (UTC+5:45), and the Chatham Islands (UTC+12:45) all convert accurately. Iran was the last country to apply DST to a half-hour offset until it abolished DST in 2022.

Does my input get sent to a server for conversion?

No. The conversion is pure client-side JavaScript using the Intl API, which means the timezone data already lives in your browser (shipped as part of the V8 or SpiderMonkey runtime via ICU). There is no fetch, no WebSocket, no analytics tracking of the specific dates or zones you pick. The dropdown options are hardcoded in the page bundle.

What happens if I pick a time during a DST transition?

On spring-forward mornings the 2:00-3:00 local hour does not exist. Inputting 2:30 resolves to 3:30 on most platforms, but behavior is spec-undefined. On fall-back mornings 1:00-2:00 happens twice and the browser usually picks the first. For safety, avoid the transition hour - use 4:00 AM instead of 2:30.

Why are there no timezone abbreviations like EST or PST in the dropdown?

Because short abbreviations are ambiguous. "EST" is Eastern Standard Time in North America but also Eastern Summer Time in Australia. "CST" refers to at least three zones. "IST" is Indian, Israel, or Irish. IANA identifiers in Continent/City form are unique by design, which is why RFC 5545 (iCalendar) mandates them.

Can it convert between a source zone and itself as the target?

It can, but you will just get back the same wall-clock time - which is the correct answer. The more useful self-conversion is between a historical moment and its current equivalent after a zone changed rules (such as Turkey leaving DST in 2016). Pick the same zone as both source and target, move the date across the rule change, and you will see the offset label update even though the displayed time does not.

What is the difference between this tool and the World Clock?

This tool is converter-mode: you pick a specific moment in one zone and see its equivalent in your chosen targets, one-shot. The World Clock is dashboard-mode: it displays the current time in many cities and ticks live every second, with no source moment selected. Use this page when you need "what will 3 PM Tokyo look like in Lisbon next Tuesday." Use World Clock when you are monitoring ongoing team coverage or live market hours.

Why do two zones with the same offset sometimes show different times?

Because a DST transition can separate them. Europe/London and Africa/Accra both sit at UTC+0 most of the year, but London enters BST (UTC+1) in late March while Accra stays at UTC+0 - so for six months they disagree by an hour. Arizona does not observe DST but Denver does, so America/Phoenix and America/Denver drift apart half the year. Always rely on the IANA city identifier, not an assumed offset.

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