Timezone Converter
Convert across UTC offsets
About This Calculator
Timezones divide the world into regions that observe a uniform local time, primarily offset from Coordinated Universal Time (UTC). There are approximately 40 different UTC offsets in use, including half-hour and quarter-hour offsets. Timezone conversion is essential for scheduling international meetings, tracking global markets, and coordinating distributed teams.
Formula
Target time = Source time + (Target UTC offset − Source UTC offset)
UTC offset ranges from UTC−12:00 to UTC+14:00
DST (Daylight Saving Time): clocks spring forward 1 hour (spring) and fall back 1 hour (autumn)
Example Calculation
Convert 10:00 AM New York (UTC−5, EST) to London (UTC+0, GMT) and Tokyo (UTC+9, JST)
- London = 10:00 AM + 5 hours = 3:00 PM GMT
- Tokyo = 10:00 AM + 14 hours = 12:00 AM (midnight) next day JST
10:00 AM EST = 15:00 GMT = 00:00 JST (next day)
Major Timezone Offsets (Standard Time)
| Timezone | UTC Offset | City |
|---|---|---|
| PST / UTC−8 | −8:00 | Los Angeles, Vancouver |
| EST / UTC−5 | −5:00 | New York, Toronto |
| GMT / UTC+0 | +0:00 | London, Dublin, Lisbon |
| CET / UTC+1 | +1:00 | Paris, Berlin, Rome |
| IST / UTC+5:30 | +5:30 | Mumbai, New Delhi |
| CST / UTC+8 | +8:00 | Beijing, Singapore, Hong Kong |
| JST / UTC+9 | +9:00 | Tokyo, Seoul |
| AEST / UTC+10 | +10:00 | Sydney, Melbourne |
Frequently Asked Questions
What is UTC and how is it different from GMT?
UTC (Coordinated Universal Time) is the global time standard, maintained by atomic clocks. GMT (Greenwich Mean Time) is a timezone at 0° longitude. For practical purposes they show the same time, but UTC is the scientific standard. UTC never observes daylight saving time.
Why do some countries have 30 or 45-minute offsets?
Some regions set their timezone to align with local solar noon rather than fitting neatly into hourly increments. India (UTC+5:30), Iran (UTC+3:30), Nepal (UTC+5:45), and several others use non-standard offsets for historical and political reasons.
How do I schedule a meeting across multiple timezones?
Find overlapping business hours. US East Coast (UTC−5) and Western Europe (UTC+1) have a 6-hour gap — morning US time (9-11 AM EST = 2-4 PM CET) is the overlap window. Asia-Pacific meetings with the US often require early morning or late evening for one party.
What is Daylight Saving Time?
DST shifts clocks forward 1 hour in spring and back in autumn in participating regions, extending evening daylight. Not all countries observe DST. The US, Canada, and most of Europe do; China, Japan, India, and most of Africa do not. DST transitions cause temporary timezone offset changes.