All-in-One Time Zone Converter

Compare multiple time zones on one visual timeline, spot overlap windows, and schedule global meetings faster.

A single converter answers one question: what is 15:00 in Berlin, in Chicago? A board answers the question people actually have, which is when nine people in seven countries can all be awake, at work and in the same call.

That second question does not get easier with practice. It gets harder with every place you add, because the number of pairs to hold in your head grows faster than the list does. Four places is eye-work; nine is arithmetic, and arithmetic done in a hurry before a calendar invite goes out is where the wrong hour comes from. This tool does the arithmetic and shows its working, so the board is still readable and the answer is still checkable.

What a board gives you that a converter cannot

• A whole day at once — forty-eight half-hour tiles per place, so an overlap is a shape you can see rather than a calculation you repeat.
• A ranked answer — the best windows for your meeting length, listed best first, with the count of places inside working hours beside each.
• An honest empty state — when no window suits everyone the tool says how close it can get, instead of promoting the least bad option.
• Clock changes on the board — the half hour in which a place moves on or off daylight saving is marked, because that is the tile that catches people out.
• Weekends handled properly — a Saturday at 10:00 looks perfect on a colour-coded grid and is not a working hour, so it is never counted as one by default.
• Every local time in one copy — one press puts the selected instant, in every place, with offsets, on the clipboard ready to paste into an invite.

The ranking is not a colour. It is a score computed over the whole day, and it is worth understanding because it tells you when to trust it and when to move the working window instead.

Three bands, not a gradient

Each half hour is placed in one of three bands for each place: inside its working window, awake but outside it, or night. The bands are categorical on purpose, because the decision a person makes about a slot is categorical — you can ask someone to take a call in their working day, you can ask a favour of someone who is awake, and you do not ask at 03:00. A weekend demotes a slot out of the working band however the clock reads, unless you have said weekends count.

A window is only as good as its worst half hour

A meeting of an hour is two consecutive half-hour tiles; ninety minutes is three. Every run of the right length is scored, and its score is the minimum across its tiles rather than the average. That distinction is the whole point: a window that is ideal for the first thirty minutes and impossible for the second averages out as acceptable and is not a meeting anybody can attend. Ties break first on how many people are at least awake, then on the total score, then in favour of the earlier window.

Most scheduling mistakes that survive a careful check are daylight-saving mistakes. They are invisible because both times are real times — they are simply real on different sides of a clock change.

The hour that does not exist, and the hour that happens twice

In New York on 8 March 2026 the clocks jump from 02:00 straight to 03:00, so 02:30 that morning never happens. On 1 November they go back, so 01:30 happens twice — once at 05:30 and once at 06:30 in universal time. A board that quietly picks one of the two is giving a confident answer to a question with two answers. Here the half hour that contains a change is ringed on the board, so you can see it before you book across it.

Offsets are dates, not places

London is one hour ahead of universal time in July and level with it in January. Sydney moves the other way, so the gap between London and Sydney swings between eight and eleven hours across a year, and for two short stretches it is neither. This is why the date control matters more than it looks: every row re-reads its offset for the day on the board, so a meeting arranged in June for December is computed for December.

The slowest part of any scheduling tool is telling it who is involved. Two things make that fast here.

Search the way people talk

All 419 zones are searchable, and the index carries the names people actually type rather than only the identifiers. Mumbai, Bombay, Delhi, India and IST all reach the same row. Pacific Time, PST, LA and San Francisco all reach another. Typing an identifier directly works too, and it wins outright — pasting America/Argentina/Salta gives you Salta, not the nearest popular city.

Paste a whole team

Every comparable tool adds places one at a time through an autocomplete, which is fine for three and tedious for nine. Paste one place per line — commas, semicolons and tabs work as separators too — and the whole list is resolved in one action. Lines that match nothing are reported back rather than skipped, because a paste of nine that produced seven rows should tell you which two it could not place.

Six steps, in the order the tool is laid out. Nothing needs an account and nothing is uploaded.

1. Add the places you need

   Search by city, country or abbreviation — Mumbai, Brazil and PST all resolve. Paste a whole list of cities into the bulk box to build a nine-person board in one action.

2. Choose the day

   Pick a date, step a day forward or back, or press Today. Every row re-reads the offset for that date, so a board built in June is still right in December.

3. Set your working hours

   The default window is 09:00 to 18:00 local. Move either end, and decide whether weekends count as working time — both change the ranking immediately.

4. Read the ranked windows

   The best times panel lists the top windows for the meeting length you chose, each labelled with how many places are inside working hours and how many are at least awake.

5. Pick a slot

   Press a window, or press any tile on the board, to select it. The panel underneath shows that exact instant in every place, with its offset and its calendar date.

6. Share it

   Copy every local time as text on any plan. On Pro, download a calendar invite that carries all of them, export the board as CSV, or copy a link that reopens the same board.

The board earns its keep the moment a single conversion stops being enough — which is usually the third participant.

Ideal use cases

• Distributed teams — find the standing slot that costs the fewest people their evening, and see which ones it costs.
• Client calls across regions — choose an hour that is inside working time on both sides, and prove it before you send the invite.
• Interview and on-call scheduling — check a candidate or an engineer is not being asked for 06:00 their time.
• Launches and maintenance windows — pick the hour that is quietest across every region you serve, not just your own.
• Conference and webinar planning — compare several candidate hours against the same audience board in one view.
• Family and friends abroad — see when a call lands in the evening at both ends rather than at breakfast on one.

A few of these explain why scheduling software gets time wrong, and all of them are handled on this board.

Key statistics

• The IANA time zone database defines around 419 distinct zones, far more than the 24 hour-wide bands people picture.
• Not every offset is a whole number of hours: India is +05:30, Nepal is +05:45, and the Chatham Islands run at +12:45 and +13:45.
• Lord Howe Island shifts its clocks by thirty minutes for daylight saving rather than the usual hour.
• The world spans 26 hours end to end, so two places can be on different calendar dates at the same instant.
• Morocco changes its clocks four times in some years because the change pauses for Ramadan.
• Roughly a third of the world observes daylight saving, and the southern hemisphere observes it in the opposite half of the year.
• Time zone rules change by legislation several times a year, which is why offsets are read from a maintained database rather than calculated.

The board removes the arithmetic. These habits remove the rest of the mistakes.

Getting a reliable answer

• Add every participant before you read the ranking — a window that is perfect for four people can be the worst one for a fifth.
• Set the date to the day of the meeting, not today, whenever the two are in different daylight-saving seasons.
• Move the working window to match reality: a team that starts at 08:00 gets a different and better answer than the default assumes.
• Check whether the top window is ringed for a clock change before you send an invite that crosses it.
• Use the reference row to see the board in the timekeeping of whoever is hosting, so the invite text matches the host's calendar.
• Paste the copied summary into the invite body — every attendee then sees their own local time without converting anything.

When not to rely on it alone

• For dates far in the future: governments change time zone rules by legislation, sometimes with weeks of notice.
• For historical dates before the modern database is authoritative in your region, where local records may disagree.
• Where legal time matters — contracts, filings, market opens — quote the offset explicitly rather than a bare local time.
• For scheduling that must survive a participant relocating; a board is a snapshot of where people are today.

A board is only useful once it leaves the tab. There are three ways out of it, and one of them is free on every plan.

A calendar invite that carries every local time

The exported invite writes its start and end in universal time rather than as a floating local time, which is the form no calendar can misread. Its description lists every place on the board with that place's local time and offset, so the information survives being forwarded to somebody who never saw the board.

A link that reopens the same board

The board link stores the places, the date, the selection and the clock format after the # in the address. That part of a URL is never sent to a server, so a link naming your colleagues' cities stays between the people you send it to. Anything in a link that does not survive validation — a zone this device does not have, a date that does not exist — is dropped and reported rather than trusted.

Every tool in this category claims to be accurate. This is what the claim is worth here.

Measured against an independent reference

Offsets are read from a transition table built once per zone, and that table is compared against your device's own maintained time zone data with zero tolerance — an offset is a whole number of minutes and either matches or does not. The comparison covers every zone across every hour of a year, a hostile set chosen so each zone breaks a different assumption, and every clock-change instant with the millisecond either side of it. The overlap ranking is checked the same way, against a second implementation that reaches the local hour through a completely different route.

Fast enough to be live

A board of nine places is 432 tiles, and every one of them is recomputed when you move the date, the clock format or the working window. Reading each tile through a fresh formatter — the way the page this replaces did — costs tens of milliseconds per repaint and makes a slider feel broken. The transition table brings the same work down by more than two orders of magnitude, which is what lets the ranking update on the same frame as the control you moved.

Everything that helps you read a board is free. The paid tier is about getting the result out of the page.

• Free — four places on the board, lists of up to 100 lines in the bulk box, the full ranking, the whole day, and copying every local time as text.
• Pro — as many places as your device can lay out, plus the calendar invite, the CSV export and the shareable board link.
• Always free — copying the selected instant in every place. A result you can read is a result you can take with you, on any plan.
• The real ceiling — there is no server, so the limit on Pro is what your own machine will lay out — not a number chosen for a pricing page.

No board, no place list, no pasted roster and no exported file is uploaded anywhere. The conversion, the ranking and the calendar file are all produced on your own device, and the shareable link keeps the board in the fragment of the address, which is the one part of a URL that is never sent anywhere. There is nothing to sign up for and nothing to delete afterwards.

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