About WorldClock.free

What this is

Search engines answer "what time is it in Tokyo" before you finish typing. That is the easy half. The half nobody serves is everything underneath it: whether the clocks there have already changed, when they change next, whether 15:00 is 3pm or 5pm, what the gap will be in November when one end springs forward and the other does not, and which hour is not the middle of somebody's night.

So every page here is computed, never written. A city page is a live clock in both formats, the IANA zone and its current offset, the exact date and time of the next daylight-saving transition, sunrise and sunset worked out from that city's own coordinates, day length and whether it is getting longer, a comparison table against twenty major cities, an overlap strip showing when a call would land in working hours at both ends, and a set of questions whose answers come from the same numbers as the page body. Nothing on it is a paragraph with a city name pasted in.

Where the data comes from

Time-zone rules: the IANA time zone database. This is the source every operating system uses. It is maintained against primary sources — government gazettes, legislative announcements — and it is the reason a page here can tell you that Australia's clocks move on 4 October rather than guessing from a rule of thumb. We update the snapshot monthly and restart, and a wrong daylight-saving date is the one bug this site treats as fatal.

Places: GeoNames, licensed CC BY 4.0. 34,086 populated places with coordinates, population, region and time zone. Roughly 900 well-known cities get a short URL like /london; every other place has a canonical page at /{country}/{city}, which is how three different Springfields all get a page of their own instead of fighting over one.

Sunrise and sunset: computed here, from the NOAA solar equations (Meeus, Astronomical Algorithms). No third-party API sits on the request path, so there is nothing to rate-limit, nothing to go down, and the times are for the exact coordinates of the place rather than the nearest big city.

How the clock stays right

The page carries our server's own timestamp. Your browser measures the gap against its own clock and renders from the corrected value, re-syncing periodically. If your laptop is four minutes fast, this page is not.

With JavaScript switched off, everything still renders — the clock simply stops ticking, and the page refreshes itself once a minute so it cannot quietly go stale. That is deliberate: the best-known personalized world clock on the internet shows literally zero clocks with JS off, because it builds its dashboard in the browser. Ours is real HTML.

Your dashboard, without an account

The board on the home page is yours to edit — add places, rename them, drag them into the order you want, set your working hours. There is no sign-up, nothing is stored on our servers, and the whole thing lives in your browser under a single key that Reset to defaults clears completely.

The share link carries your labels and your ordering in plain, readable text, so you can send someone a board with "Mum", "Kenji" and "NY office" on it and they see exactly what you built. Opening a shared link never touches the recipient's own board — there is a button to adopt it, and until they press it nothing changes.

What it costs

Nothing. The domain says free and means it. There is no paid tier today, no account to create, no feature held back, and no interstitial. If a paid ad-free option ever appears it will be cheap and optional, and the free version will not get worse to make room for it. See what it costs.

A sibling site

Developer-facing time tooling — UTC and epoch conversion, ISO 8601 formats, a free time API — lives at utctime.app. The split is deliberate: places here, zones and timestamps there, no duplicated pages between the two.

Found something wrong?

A wrong time is worth telling us about, and we would rather hear it than not. Get in touch — include the page and what your own clock said.