⏱️ Time & Date
World clock, timezone converter, date calculator, countdown timer
Convert times between cities and time zones worldwide. Free world clock.
Open tool →Add or subtract days from a date, find days between two dates.
Open tool →Online countdown timer and stopwatch. Set any duration.
Open tool →How many weeks in a year, seconds in a day, and more time conversions.
Open tool →Time zones, date arithmetic, elapsed durations and countdowns — the calculations that are easy to get subtly wrong by hand because calendars refuse to behave arithmetically.
Time zone work in particular is worth doing with a tool. Offsets shift with daylight saving, the shift dates differ by country, and the answer you want is usually "what time is it there when it is this time here", which is two conversions rather than one.
Which tool do I want?
| If you… | Use |
|---|---|
| You are scheduling across countries | Time Zone Converter |
| You need days between dates, or a date N days out | Date Calculator |
| You are adding or subtracting hours and minutes | Time Calculator |
| You want time remaining until an event | Countdown Timer |
The offset is a property of the date, not the place
"New York is UTC−5" is true in January and wrong in July, when it is UTC−4. Scheduling a recurring call by fixed offset works until one side changes clocks and the other has not yet — and because the EU and US switch on different weekends, there are a couple of weeks each year when the usual gap between London and New York is off by an hour.
The reliable approach is to store the zone name rather than the offset: Europe/Oslo, not UTC+2. The zone name plus a date determines the offset; an offset alone determines nothing.
Then there are the edges. Not every zone is a whole hour off — India is UTC+5:30, Nepal UTC+5:45. Some places skip a day: when Samoa crossed the date line in 2011, 30 December simply did not exist. And on a spring-forward day one local hour never happens, so a meeting set for 02:30 that morning is a time with no instant attached to it.