Online clock with seconds

A clock that is truly on time

Your computer or phone clock can be several seconds fast or slow. This page measures its offset from our server’s clock, itself synchronised with reference time servers, and corrects the display: the time shown is accurate to a few hundredths of a second, with the margin shown below the clock.

In full screen, the digits fill the screen and the page asks the browser to keep the screen awake: handy for keeping an eye on the time during an exam, when a ticket office or an online sale opens, or to start a live stream on the dot. Press Esc to go back.

The countdown targets a time in the city shown, to the second: when ticket sales open, the end of an exam, the start of a live stream. If that time has already passed today, it targets tomorrow. The clocks added below let you follow several cities at once; your settings are kept in your browser.

To set your device’s clock, see exact time and clock synchronisation. For the world reference time, see UTC time.