How to use

This page is set to 5 minutes. Press Start to begin the countdown, or choose another time under Set the time.
Press Start to begin the countdown. The remaining time is calculated as the end time minus the current time, so it remains correct after you switch tabs or your computer goes to sleep.
At the end, the alarm plays for up to 60 seconds. Press Stop the alarm to end it sooner. The alarm is scheduled when you press Start, so it also plays on time in a background tab.
With Keep the screen on while running turned on, your phone or computer will not turn off the screen during the countdown. In full screen, the display is enlarged to fit the screen.
Keyboard shortcuts: Space starts, pauses or resumes the timer, and R resets it.
This tool runs in your browser. What you enter and your timing records are stored only in this browser and are not uploaded.

Common questions

Does the timer slow down in a background tab?: No. Browsers update background tabs less often, but this timer calculates the remaining time from the end time on every update, so the display is correct as soon as you return.
Will the alarm play when my phone is locked?: Some mobile browsers pause web pages when the phone is locked, so the alarm may not play. If you need the alarm, please turn on Keep the screen on while running and keep this page in the foreground.
Does the timer continue after I reload the page?: Yes. The end time is stored in this browser, so the countdown continues after a reload. The browser requires one click on the page before the alarm can play again, and the page will prompt you to do so.
Why is there no sound?: Please check the volume and mute switch of your device, and make sure that Play an alarm at the end is turned on.