How to convert a time between zones
- Choose the zone the time is in. It starts as your own zone.
- Pick the date and type the time, for example
15:00or3 pm. - Read the same moment in every zone in the table. Add any city with Add a time zone. Your list is saved in this browser.
The date matters. Many countries change their clocks for daylight saving time (DST), so the gap between two cities can change during the year. The converter works out the offset for the exact date you choose.
Worked example: IST to New York across a DST change
India Standard Time (IST) is UTC+5:30 all year. New York is UTC−5 in winter (EST) and UTC−4 in summer (EDT). In 2026, US clocks go forward on 8 March and back on 1 November.
| Time in India (IST) | UTC | New York | Gap |
|---|---|---|---|
| Fri 6 Mar 2026, 19:30 | 14:00 | 09:00 EST | 10 h 30 min |
| Fri 13 Mar 2026, 19:30 | 14:00 | 10:00 EDT | 9 h 30 min |
| Fri 6 Nov 2026, 19:30 | 14:00 | 09:00 EST | 10 h 30 min |
The formula is simple once you know both offsets: local time = UTC + offset. So 19:30 IST − 5:30 = 14:00 UTC, and 14:00 UTC − 4:00 = 10:00 EDT. The hard part is knowing the right offset for each date, which the converter does for you.
Common time zones and their offsets
| Place | IANA zone | Standard time | Summer time (DST) |
|---|---|---|---|
| India | Asia/Kolkata | UTC+5:30 (IST) | None |
| United Kingdom | Europe/London | UTC+0 (GMT) | UTC+1 (BST) |
| New York | America/New_York | UTC−5 (EST) | UTC−4 (EDT) |
| California | America/Los_Angeles | UTC−8 (PST) | UTC−7 (PDT) |
| Dubai | Asia/Dubai | UTC+4 | None |
| Singapore | Asia/Singapore | UTC+8 | None |
| Sydney | Australia/Sydney | UTC+10 (AEST) | UTC+11 (AEDT, October to April) |
UTC vs GMT
UTC (Coordinated Universal Time) is the world's reference time, kept by atomic clocks. Every time zone is described as an offset from it. GMT (Greenwich Mean Time) is the time zone of the UK in winter. For everyday use, GMT and UTC show the same clock time. But GMT is a zone, while UTC is a standard. And the UK is not on GMT in summer: it uses BST, which is UTC+1.
Daylight saving time
In daylight saving time, clocks move forward one hour in spring and back one hour in autumn. The USA, Canada, the UK and the EU use it, but on different dates. For a few weeks each year, the gap between London and New York is 4 hours instead of the usual 5. Southern-hemisphere places such as Sydney change in the opposite season.
Two odd cases follow. When clocks go forward, an hour is skipped: 02:30 on that day does not exist in New York. The converter moves such a time forward and tells you. When clocks go back, an hour happens twice. The converter uses the first one and says so.
IST: one time zone, no DST
All of India uses IST, UTC+5:30, and has not used daylight saving time for decades. So India's gap to the UK or the USA changes twice a year, but only because those countries change their clocks. The half-hour offset is why IST often shows as 30 minutes past the hour elsewhere. Nepal (UTC+5:45) and parts of Australia also use offsets that are not whole hours.
Tips for scheduling across zones
- Always write the zone with the time, for example "15:00 IST" or "10:00 New York time".
- Prefer city names to abbreviations. "CST" can mean US Central, China or Cuba Standard Time.
- Check meetings again in the weeks around March, April, October and November, when DST starts or ends somewhere.
- For deadlines in days rather than hours, use the date calculator.
The converter uses the time zone database built into your browser. Keep your browser up to date to get the latest rule changes.
Frequently asked questions
What is the time difference between India and the UK?
What is the time difference between IST and EST?
Is GMT the same as UTC?
Does India have daylight saving time?
Does this converter handle daylight saving time?
Why is my time zone list still there when I come back?
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