Time & Date
Work across time zones without doing the arithmetic yourself
Time is the one measurement that changes depending on where you are standing, and the rules are not tidy. India is five and a half hours ahead of UTC and Nepal is five and three quarters. Half the world moves its clocks twice a year and the other half does not, and the two halves that do move them on different dates, so the gap between two cities is not a fixed number. These tools work from the time-zone database your browser already carries rather than from remembered offsets, which is the only way to get the awkward weeks right. They run on your device, and they keep working with the network off.
What people use these for
- See what time it is right now in several cities at once
- Find an hour that falls inside working hours in every country on the call
- Check whether it is already tomorrow somewhere before you send something
- Work out how long there is between two dates, or between two times
- Count down to a deadline, or find which week of the year a date falls in
Frequently asked questions
- Do these handle daylight saving?
- Yes, and by asking the time-zone database rather than storing offsets. That distinction matters more than it sounds: for about three weeks each spring, London is four hours from New York instead of five, because the two countries change their clocks on different dates. Anything that remembers one number per pair of cities is wrong for those weeks, every year.
- Do they work with half-hour and quarter-hour time zones?
- Yes. India at five and a half hours, Nepal at five and three quarters, Adelaide at nine and a half and the Chatham Islands at twelve and three quarters are all handled the same way as any whole-hour zone, and the times shown are the real local times rather than the nearest rounded hour.
- Is anything I type sent anywhere?
- No. Every one of these runs in your browser using the time-zone rules that ship with it, so there is nothing to upload and no server to call. You can turn the network off and keep using them, and the list of cities you are watching is stored on your own device only.
- Will the time be right if my computer's clock is wrong?
- Converting a time you give it will be, because that is arithmetic and does not depend on your clock. The live readouts will not, because they read your device. A wrong time zone setting on your device changes nothing at all, since every calculation here names the zone it is working in rather than assuming yours.