Time Zone Converter

Take one date and time and read it across every zone that matters, with UTC offsets and day shifts shown.

Runs on your deviceConvertersWorkingNo account needed

What this tool does

Time Zone Converter resolves what you type to a single absolute instant, then renders that instant in each zone you have chosen. The heavy lifting is done by the browser's own Intl date engine and the IANA zone database shipped with it, so each row carries the rules that actually applied on that date — not a fixed offset applied to every month of the year. Each row of the table gives the zone, the local wall clock, the UTC offset, the short name the browser holds for that zone at that moment, and whether the local date is the same day, a day ahead or a day behind the date in the source zone. Treat that short name for what it is: a real abbreviation only where the browser's data carries one, such as EDT, PDT or GMT, and for most of the world simply the offset again — GMT+5:30 for Kolkata, GMT+9 for Tokyo.

The input box takes one time per line, so a whole set of candidate slots can be compared in a single pass. It understands YYYY-MM-DD with an optional HH:MM or HH:MM:SS, am or pm, a bare clock time such as 14:00 or 9 pm (read as today in the source zone), and the word now — which is also what an empty box means. If a line carries its own offset, such as 2026-07-01T12:00Z or a trailing +05:30, that offset wins and the Time is in setting is ignored for that line. Seconds only appear in the output when at least one line you typed had them.

Show zones offers four ready-made lists — around the world, Americas, Europe and Asia-Pacific — plus all sixty-nine listed zones, or a custom list you type yourself. That custom field accepts full IANA names like Europe/Paris, the bare city from a listed name such as Tokyo, and common abbreviations such as PST or IST. Abbreviations are mapped deliberately rather than handed to the engine, because engines resolve the legacy ones in ways nobody means: EST would otherwise land on America/Panama, which never observes daylight saving. Duplicates are dropped, the source zone is always included so you can see where you started, and rows are sorted by UTC offset unless you turn that off.

Two limits are worth knowing before you rely on an answer. Abbreviations are ambiguous in the real world and this tool has to pick one meaning each: IST is India here rather than Ireland or Israel, CST is Chicago rather than China, and BST is London. Type the full IANA name when the difference matters. Second, this converts instants; it does not schedule. There is no working-hours grid, no shading of who is asleep and no suggestion of a best slot — you list the times you are considering and read off what each one means elsewhere. The conversion is arithmetic done in this browser tab, so the dates you type are not uploaded anywhere and the tool keeps working with the network off.

How to use it

  1. Say which zone your time is in. The Time is in list defaults to UTC. Set it to the zone the time was written in — a line that carries its own offset overrides it anyway.
  2. Type the times, one per line. 2026-03-14 09:30, 14:00, 9 pm or now. Leave the box empty and the current moment is used. Several lines are converted in one pass and labelled in the table.
  3. Choose which zones to show. Pick a preset, all listed zones, or Custom list and name your own — IANA ids like Europe/Paris, cities like Tokyo, or abbreviations like PST, separated by commas or newlines.
  4. Set the clock and the ordering. 24-hour or 12-hour display, and Sort zones by UTC offset on or off. Sorted, the list reads west to east and the day boundary is easy to spot.
  5. Read the table. Each row shows the local time, the UTC offset with whatever short name the browser has for that zone, and whether it lands on the same day as the source zone, a day ahead or a day behind.

Processing & privacy

Runs on your device. Your file is processed directly in this browser.

Common use cases

Fixing a meeting time across three offices

Put two or three candidate slots on separate lines and read all of them at once, rather than converting each one and losing track of which was which.

Announcing a maintenance window

Write the window in UTC, convert it into the zones your users are in, and publish local times with the day shift already accounted for.

Checking a deadline someone else set

A submission closing at 23:59 in one zone may already have passed in yours. The day column makes that visible instead of leaving it to arithmetic.

Reading a timestamp from a log

A line ending in Z or +05:30 carries its own offset, so paste it as it stands and see the same instant in the zones your colleagues work in.

Seeing whether a weekly call moves

Convert the same clock time on a date either side of a clocks-change weekend. Zones shift on different dates, so a call that was one hour apart can become two.

Questions

Do the times I type leave this tab?
No. The conversion runs against the zone database the browser already carries, so the dates and times you type are never transmitted, logged or stored, and the tool still works with the network off.
Which zone does IST mean?
Asia/Kolkata. Abbreviations are not unique across the world, so each one here is mapped to a single zone: CST is Chicago rather than China, BST is London, and PST is Los Angeles. When the difference matters, type the full IANA name such as Asia/Jerusalem instead.
What happens on the night the clocks change?
Both awkward cases are flagged rather than hidden. A wall time that never happens, such as 02:30 during a spring-forward, is moved on by the length of the jump — 02:30 becomes 03:30 — and a note names the time actually used. A wall time that happens twice during an autumn fall-back is converted using the first, pre-transition occurrence, and a note names the offset used.
Can I use a zone that is not in the list?
Yes. Choose Custom list and type any IANA identifier your browser recognises — Africa/Accra, Pacific/Chatham, America/Argentina/Cordoba. The sixty-nine listed zones are only what the presets and the source dropdown offer; an unrecognised name stops the run and says so rather than being skipped.
Will it find a time that suits everyone?
No. It converts the instants you give it and nothing more — there is no working-hours overlap, no shading of unsociable hours and no recommended slot. List the candidates yourself and judge from the table.
Are historical and future dates converted correctly?
They are converted with the rules the browser's zone database holds for that date, which is why a July conversion and a January one can differ by an hour. The caveat is the database itself: when a country changes its rules at short notice, the result stays on the old rules until the browser is updated. Dates from before standard time was adopted carry local mean time offsets such as UTC−04:56, and the offset column rounds those to the nearest minute.
Why is my date shown at 00:00?
A date with no time is read as midnight at the start of that day in the source zone. Add a time to the line if you meant something else, and note that an impossible date such as 30 February is refused outright rather than rolled into the next month.

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