About whattimein.world

whattimein.world shows the current local time, date, time zone and daylight saving status for 469 cities in 96 countries, explains 52 time zone abbreviations, and offers 156 ready-made conversions between time zones and cities. Around that sit the tools people reach for next: a time zone converter for any date, a meeting planner that finds overlapping working hours, a world clock, countdown timers, an alarm, a stopwatch and date and hours calculators.

There are no accounts, no paywalls and no adverts. Everything runs in the page you are looking at.

Every time on the site comes from the IANA time zone database, the same rule set that phones, computers and servers use. Cities are stored with their IANA zone identifier, such as America/New_York, never with a fixed offset, so daylight saving changes, half-hour and quarter-hour offsets, and historical rule changes are handled by the database rather than by us.

Pages are rendered on the server with a recent snapshot and then the clocks tick in your browser from your device’s clock. If your device clock is wrong, the times shown will be wrong by the same amount; the time zone rules still apply correctly.

Sunrise, sunset and day length are computed from each city’s coordinates with standard solar-position formulas, accurate to about a minute. Time differences between places are calculated for the specific date you choose, so a comparison in March can differ from one in November when only one side observes daylight saving time.

• City and country records, including coordinates and population, come from GeoNames under the Creative Commons Attribution 4.0 licence.
• Time zone rules come from the IANA time zone database through the standard internationalisation features of the browser and of the server runtime.
• City photographs come from Wikimedia Commons under free licences. Each photo carries its author and licence next to the image, linking to the original file.
• No paid data services are used, and nothing is fetched from third parties while you use the site.

Time zone abbreviations are ambiguous: CST is used for Central Standard Time in North America, China Standard Time and Cuba Standard Time. Pages about abbreviations say which meaning they cover and when a region switches between standard and daylight names, and they never label a daylight-time period with the standard-time abbreviation.

If you spot a wrong time, an outdated daylight saving rule or a city that is missing, please tell us. The site is open source on GitHub, where every calculation and data rule can be inspected.