Time zone converter & meeting planner

Pick a time in your time zone and up to three other places. You get the local time in each, a 24-hour timeline of who is at work, awake or asleep, and the hours when everyone is on the clock.

Inputs

Clock changes depend on the date. Leave it on today or pick the day of your meeting.

Time in London

14:00same day

When it is 09:00 in New York on 2026-10-01. London is +5 h from New York.

Everyone is at work at 09:00 New York time.

Shared work hours
3 h
Best window
09:00–12:00
New York offset
UTC−4
London offset
UTC+1
New York day, 2026-10-01, hour by hour in each place
Shared work hoursNew York UTC−4New York: 0000New York: 01New York: 02New York: 0303New York: 04New York: 05New York: 0606New York: 07New York: 08New York: 0909New York: 10New York: 11New York: 1212New York: 13New York: 14New York: 1515New York: 16New York: 17New York: 1818New York: 19New York: 20New York: 2121New York: 22New York: 23London UTC+1London: 0505London: 06London: 07London: 0808London: 09London: 10London: 1111London: 12London: 13London: 1414London: 15London: 16London: 1717London: 18London: 19London: 2020London: 21London: 22London: 2323London: 00 (a different date)London: 01 (a different date)London: 02 (a different date)02London: 03 (a different date)London: 04 (a different date)
  • At work
  • Awake, outside work
  • Night

When it is 09:00 in New York on 2026-10-01 it is 14:00 in London. Everyone is at work between 09:00–12:00 New York time, 3 hours in all. The chart shows each place's hours across the New York day, coloured for work, awake and asleep.

How it works

A place is an IANA zone such as America/New_York. Every time the calculator needs to convert, it asks the browser two questions through Intl.DateTimeFormat: what does this zone’s wall clock read at this instant, and so how far is it from UTC right now?

offset(zone, t)   = wall clock of the zone at t, read as if it were UTC, minus t
instant(zone, y-m-d h:mm) = the t at which the zone’s clock reads that time
time there        = wall clock of the other zone at the same instant
  • The day is laid out hour by hour in your zone (23 or 25 hours on a clock-change day) and each row reads the other place’s clock at those same instants.
  • Colours. Work is the working day you set, awake is 07:00 to 22:00 outside it, and the rest is night.
  • Shared hours are the 15-minute slots in which every place is at work.
  • Date. The date is an input because the offset depends on it. A blank date means today in your zone.

Worked example

It is 09:00 in New York on 15 July 2026 (UTC−4). The same instant is:

  • 14:00 in London (UTC+1), 18:30 in Mumbai (UTC+5:30), 22:00 in Tokyo (UTC+9) and 23:00 in Sydney (UTC+10).

New York and London share three working hours, 09:00 to 12:00 New York time (14:00 to 17:00 in London). New York and Mumbai share none, because Mumbai’s working day (9 to 5) is 23:30 to 07:30 in New York.

Tips for scheduling across zones

  • Check the date, not just the cities. The gap between two places can change twice a year on different weekends. Put the real meeting date in.
  • Mind the date line. A late evening in New York is already tomorrow in Tokyo. The result shows “next day” when that happens.
  • Half-hour zones shrink the overlap. India’s 5:30 offset means a window that looks like 4 hours on the hour can be 3.5.
  • Not every place moves its clocks. Arizona, Japan, India and Dubai never change, so their gap to a place that does moves twice a year.

FAQ

Why is New York sometimes 4 hours behind London and sometimes 5?

The US and the UK change their clocks on different dates. The US moves on the second Sunday of March and the first Sunday of November; the UK on the last Sundays of March and October. In 2026 New York is only 4 hours behind from 8 to 29 March and again from 25 October to 1 November.

Where do the offsets come from?

From your browser's built-in copy of the IANA time zone database, read through the standard Intl.DateTimeFormat. Nothing in the calculator is a typed-in UTC offset, so daylight saving changes and new government rules arrive with your browser's updates.

How are the shared working hours worked out?

The calculator steps through your chosen day in 15-minute slots and counts the slots when every place is inside the working day you set (9 to 5 by default). It reports the total and the longest unbroken window, in your time. Places with half-hour or 45-minute offsets, such as India and Nepal, are handled correctly.

What does "awake" mean on the timeline?

Between 07:00 and 22:00 outside working hours. Before 7 a.m. or from 10 p.m. the cell is shaded as night. The hours are our rule of thumb; change the workday to match your teams.

What if my time falls in a clock change?

A time that does not exist, such as 02:30 when US clocks spring forward, is read as 03:30. A time that happens twice, such as 01:30 when they fall back, is read as the first. The page tells you when a clock changes on the day you picked.

Sources

  1. Time Zone Database (tz release 2026e, 29 September 2026), IANA, source files by Paul Eggert and contributors. The rules the browser's time zone data follows. Asia/Kolkata is 5:30 and Asia/Kathmandu 5:45 with no daylight saving; the US rule is the second Sunday of March at 2:00 to the first Sunday of November at 2:00; the EU rule is the last Sunday of March to the last Sunday of October at 01:00 UTC; Australia's is the first Sunday of April and of October.
  2. When do the clocks change?, GOV.UK. UK clocks go forward on 29 March and back on 25 October 2026 (30 March and 26 October 2025; 28 March and 31 October 2027; 26 March and 29 October 2028), at 1am and 2am.

Formula and sources last checked September 30, 2026. How we test formulas.

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