Online Timer

Yes. Browsers slow down background tabs, so timers that count down second by second fall behind. This one calculates from the finish time instead, so it stays exact even if the tab is hidden or the screen turns off. The remaining time also appears in the tab title.

An alarm sound plays and the display pulses gently. The alarm repeats for up to one minute until you press Stop alarm. If you allow browser notifications, you also get a desktop alert while working in another tab.

Yes. Add the time to the address: timer.html?m=5 opens a 5-minute timer, timer.html?m=90 opens an hour and a half, and timer.html?m=25&autostart=1 starts a 25-minute timer right away. If the browser blocks sound for a timer started that way, a notice appears and one click or tap on the page lets the alarm play. Copy link to this time puts the address for the time you have set on your clipboard.

Open Alarm sound under the buttons to choose beeps, a low tone, a bell or no sound, and to set the volume to one of three levels. Test plays the sound, and your choice is remembered in this browser.

Yes. Once it starts, the −1 min, +1 min and +5 min buttons change the remaining time straight away. After it finishes, +1 min or +5 min starts a fresh countdown of that length.

Press Full screen or the F key and the digits grow to fill the display, which suits a classroom or meeting room. Close or Esc returns to the page. Space starts and pauses, and R resets.