Online Clock
Your current local time, with seconds. Switch to a 24-hour clock or go fullscreen.
Clock options
The buttons under the clock switch between 12-hour and 24-hour time, show or hide the seconds and the date, and turn the time zone line on or off. Your choices are remembered on this device, so the clock looks the same the next time you open it - and if you have the site open in two tabs, changing a setting in one updates the other.
Fullscreen turns the page into a large, plain digital clock, which is the point of this page for most people: something readable from across a room, on a spare monitor or a phone propped up on a desk. Press Escape to come back.
Where this time comes from
The clock shows the time your own device is set to, formatted for the time zone your browser reports. Nothing is looked up over the network and your location is never used - if your device clock or time zone is wrong, this page will be wrong in exactly the same way, which also means you can use it to check.
It updates on the real second boundary rather than on a timer that counts up, so it will not slowly fall behind, and it re-reads the clock the moment you come back to the tab.