Time Zone Calculator
Pick a date, a time and the city you are converting from, then press Convert to All Timezones. The calculator lists that moment in all 20 cities it covers, including London, Mumbai and Tokyo. Each city follows its own daylight saving rules, so New York is on UTC−5 in January and UTC−4 in July, and Sydney is on UTC+11 in January and UTC+10 in July. The offset column shows the one in force at that moment.
How to use the Time Zone Calculator
- Enter your numbers in the Time Zone Calculator above.
- Press the Convert to All Timezones button to see the result.
- To try other numbers, change any value and press the button again.
The time zone conversion
Target time = Source time − Source offset + Target offset
The calculator turns your time into UTC by taking off the source city's offset on that date. Then it adds each target city's offset at that moment. The offsets come from the IANA time zone database built into your browser, which records when each city starts and ends daylight saving time. A time in the hour skipped when clocks jump forward is read as one hour later, so 02:30 on March 8, 2026 in New York becomes 03:30. A time in the hour repeated when clocks go back is read as the first of the two.
Worked example
Choose New York, 15:00 and a date in January. London shows 20:00 the same day, because New York is on UTC−5 and London on UTC+0. Mumbai shows 01:30 the next day, 10:30 ahead. Now pick a date in July. New York is on daylight time at UTC−4 and London on UTC+1, so London still shows 20:00. Mumbai has no daylight saving time and stays on UTC+5:30, so it shows 00:30 the next day, 9:30 ahead.
Frequently asked questions
What is UTC?
Coordinated Universal Time, the reference clock every time zone is measured from. For everyday use it equals GMT. New York in winter is UTC−5, five hours behind it.
Does the calculator adjust for daylight saving time?
Yes. Each city gets the offset in force on the date and time you enter. New York, Toronto, Chicago and Los Angeles move an hour forward from March 8 to November 1, 2026. London, Paris and Berlin do the same from March 29 to October 25, and Cairo from April 24 to October 29. Sydney and Auckland run on summer time from late September or early October until early April, so they are an hour further ahead in January than in July. Tokyo, Dubai, Mumbai and the other cities without daylight saving keep one offset all year.
Does DST apply everywhere?
No. Most of the US and Europe observe DST; Arizona, Hawaii, most of Asia, Africa and South America do not. DST start/end dates vary by region too.
When is DST in 2026?
In the US, DST runs March 8 to November 1, 2026. In Europe (Central European Summer Time), DST runs March 29 to October 25, 2026.