Time Zone Calculator
Convert a date and time between any two time zones, with daylight saving handled automatically
About This Tool
Pick a date and time, choose the zone it's in, and choose the zone you want to convert it to. The tool accounts for daylight saving time automatically based on the date you select, using each region's real time zone rules rather than a fixed offset.
Common Time Zone Reference
| Zone | Standard UTC Offset |
|---|---|
| Los Angeles (PT) | UTC-8 (UTC-7 in summer) |
| New York (ET) | UTC-5 (UTC-4 in summer) |
| London (GMT) | UTC+0 (UTC+1 in summer) |
| Karachi / Islamabad (PKT) | UTC+5 |
| Mumbai / New Delhi (IST) | UTC+5:30 |
| Dubai | UTC+4 |
| Beijing / Shanghai | UTC+8 |
| Tokyo | UTC+9 |
| Sydney (AEST) | UTC+10 (UTC+11 in summer) |
Frequently Asked Questions
What's the difference between UTC and GMT?
UTC is the atomic-clock time standard the world coordinates against, while GMT is technically a specific time zone used in parts of the UK and West Africa. In practice the two read the same time and are used interchangeably for everyday scheduling.
Does UTC change for daylight saving time?
No. UTC stays fixed all year. Only local time zones that observe daylight saving shift their offset from UTC, typically by one hour, during part of the year.
Why do some time zones use a 30 or 45-minute offset instead of a full hour?
A handful of countries, including India and Iran, set their standard time at a half-hour or 45-minute offset from neighboring zones, generally to better match local geography rather than sitting on a clean hourly line.
How does this tool handle daylight saving time automatically?
It reads the real time zone rules for the date you select, so if either location is observing daylight saving on that date, the conversion reflects the correct seasonal offset rather than a fixed year-round number.
What should I use when scheduling across countries?
Abbreviations like EST or IST are fine for casual conversation but get ambiguous across borders. For anything official, state the city name plus the exact date and time, or use a UTC offset so there's no room for misreading.
Why did the time difference between two cities change from last month?
One of the two zones likely started or ended daylight saving time. Since not every country observes DST, or observes it on the same dates, the gap between two clocks can shift more than once a year.
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