How We Calculate

Every figure on this site is produced by one of four calculations. This page explains each one, and says where it can be wrong — because a site about time that will not admit its own error bars is not much use.

The current time

WorldClock.to requests a millisecond timestamp from its own server, measures the browser-to-server round trip and estimates the network midpoint. That produces a server-time offset, after which the page ticks locally using a monotonic browser timer and periodically re-syncs in the background. IANA time zone rules are applied to that synchronised instant. If synchronisation is temporarily unavailable, the display falls back to the device clock until the next successful sync.

Time zones, offsets and daylight saving

Zone names, UTC offsets and clock-change dates all come from the IANA time zone database, which is updated when a government actually publishes a change. That means a page here reflects the law as it stands, not as it has been proposed — a bill that has passed one chamber of a legislature changes nothing until it is law and the database follows. It also means there is a lag: when a country announces a change at short notice, the database, your device and this site all catch up in that order.

Sunrise, sunset and day length

Sunrise and sunset use the same solar-position model as the live city components. The horizon event is calculated at about −0.833° solar altitude, the standard apparent-horizon approximation for the solar disc plus ordinary atmospheric refraction. The coordinates represent one point in the city, and the model does not know about a hill, skyline, viewing elevation or unusual refraction, so a local observed horizon crossing can differ.

Prayer times and Ramadan timetables

Prayer and Ramadan pages first resolve the selected city’s coordinates and civil time zone, then apply the site operator’s prayer-method setting and a separate Asr convention. Standard Asr uses the one-shadow convention; Hanafi uses the two-shadow convention. If Fajr or Isha twilight cannot be resolved while sunrise and sunset still occur, the engine substitutes one-seventh of the night for the missing Fajr/Isha boundary. During polar day or polar night the fallback can still be unavailable. No extra per-prayer minute adjustments are applied by the bundled calculator. These are calculated planning times, not religious rulings; use the timetable or Ramadan announcement followed by your local mosque or authority for observance.

How your location is worked out

In three steps, in order. Your browser’s time zone gives an immediate region. A free IP lookup then narrows that to a city — no permission is needed and nothing is stored on our side. Your exact coordinates are only ever requested if you press “Use my exact location” yourself, and the browser asks you before sharing anything. You can also just pick your city by hand, which overrides all of it.

City directory data

The city directory stores each location’s name, latitude, longitude and IANA time-zone identifier locally in the theme. Geographic records are maintained from open or attribution-compatible references, including the SimpleMaps Basic World Cities database (Creative Commons Attribution 4.0). Time-zone identifiers are checked against the IANA database. Coordinates are used as calculation inputs; they are not copied into editorial prose to manufacture unique pages.

Editorial and technical responsibility

Editorial and technical responsibility rests with the WorldClock.to site publisher and maintainer, reachable at [email protected]. That responsibility covers calculation logic, page templates, bundled location data, factual source checks and corrections. Changes to time-zone rules, coordinates, event dates and calculation explanations are checked against primary or authoritative sources before managed data is changed. No named external reviewer, qualification or credential is claimed unless it is explicitly identified and verifiable.

Editorial review

The written explanations on this site are checked against primary sources — the time zone database, government publications and official announcements — rather than against other time websites. Facts that change on a schedule, such as pending legislation, carry the date they were last checked. If you find an error, the contact page is the fastest way to have it fixed.