How to use this calculator
- Enter or choose date.
- Enter or choose time.
- Enter or choose from.
- Enter or choose to.
- The converted time updates as you type. Use Copy result or Share to keep it.
Method
UTC = Local time − Source offset; Target time = UTC + Target offset. Offsets come from the IANA time zone database for that exact instant, including daylight saving time.
- Offset
- hours ahead of (+) or behind (−) UTC at that moment
Worked example
- On 1 July New York is on daylight time (EDT), UTC−4, so 12:00 there is 16:00 UTC.
- London is on British Summer Time, UTC+1, so 16:00 UTC is 17:00.
- London is 5 hours ahead of New York on that date.
Noon in New York on 1 July 2026 is 5 pm the same day in London.
What the result means
The difference between two places can change during the year because countries start and end daylight saving time on different dates (for example, the US and UK change clocks on different weekends in March and autumn).
Assumptions and limits
- Time zone rules are those in the IANA database shipped with your browser.
- A local time that is skipped when clocks go forward cannot be converted; a time that happens twice when clocks go back uses the first occurrence.
- Future dates use today’s known rules; governments sometimes change them at short notice.
Questions
Why is the difference between New York and London sometimes 4 hours?
The US moves its clocks forward on the second Sunday of March and back on the first Sunday of November, while the UK changes on the last Sundays of March and October. In the weeks between, the gap is 4 hours instead of 5.
Does India use daylight saving time?
No. India uses UTC+05:30 all year, so its difference from places that do use daylight saving time changes by an hour twice a year.