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Time Zone Calculator

Convert time between zones and plan meetings

Source Time

Target Time Zones

GMT/BST (London)
Japan Time (Tokyo)
Sydney Time (AEDT)

Options

GMT/BST (London)

UTC+1 (DST)
14:39
Sat, Jun 13 • Today

Japan Time (Tokyo)

UTC+9 (DST)
22:39
Sat, Jun 13 • Today

Sydney Time (AEDT)

UTC+10
23:39
Sat, Jun 13 • Today

Quick Tips

  • • Business hours: 9 AM - 5 PM local time
  • • DST changes occur at different times globally
  • • Some regions don't observe DST
  • • UTC never changes for DST

How it works

A time zone converter translates a time from one zone to another by applying the difference in UTC offsets. Each zone is defined as a fixed offset from Coordinated Universal Time (UTC), so converting is just adding the offset gap.

Zone conversion

Target time = source time + (target UTC offset − source UTC offset)
UTC offset
each zone's hours ahead of/behind UTC

Worked example

  • 3:00 PM in New York (UTC−5)
  • Convert to London (UTC+0)
  1. Difference = 0 − (−5) = +5 hours

It's 8:00 PM in London.

Good to know

  • Daylight saving time shifts offsets seasonally, and not every region observes it — check the date.
  • The international date line means some conversions change the calendar day.
  • Scheduling across zones is easier in UTC, then convert for each participant.

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