Online Timer and Stopwatch
A countdown timer with an alarm, and a stopwatch with lap times.
About this tool
A countdown timer with an alarm sound and a stopwatch with lap times. Press the space bar to start or pause. It keeps accurate time even if the tab is in the background, because it measures elapsed time rather than counting ticks.
Set a countdown for cooking, workouts, study sessions or presentations, and hear an alarm when the time is up. Switch to the stopwatch to time a run or a task and record lap times. It runs in your browser with no download or account.
How to use the Online Timer and Stopwatch
- Choose Timer or Stopwatch at the top.
- For the timer, enter hours, minutes and seconds, or press a preset such as 5 min or 25 min.
- Press Start. Press Pause to stop the clock, and Resume to carry on.
- In stopwatch mode, press Lap to record the current time without stopping.
- Press Reset to clear the time and laps.
A 25-minute focus session
Press the 25 min preset and the display shows 25:00. Press Start (or the space bar) and work until the alarm sounds three short beeps and the tab title changes to "Time is up!". Take a 5-minute break by pressing the 5 min preset and Start again. This is the Pomodoro technique: four 25-minute sessions with short breaks, then a longer break.
How the timer keeps time
Browsers slow down timers in background tabs to save battery, so a timer that counts one tick per second can drift. This one records the exact moment you press Start and works out the elapsed time from the computer's clock on every update, so it stays accurate even when the tab is hidden. The display updates smoothly while visible. The alarm uses your browser's audio, so make sure the tab is not muted and your volume is on. If the computer goes to sleep the alarm cannot play until it wakes, but the remaining time is still correct.
Frequently asked questions
How do I set a timer for 10 minutes?
Choose Timer, press the 10 min preset (or enter 10 in Minutes) and press Start. An alarm sounds when it reaches zero.
Will the timer keep running if I switch tabs?
Yes. The time is calculated from the clock, not from ticks, so it stays accurate in a background tab. Keep the tab open, because closing it stops the timer.
Can I use the stopwatch to record laps?
Yes. Switch to Stopwatch, press Start, then press Lap each time you want to record a split. Laps are listed newest first.
Is there a keyboard shortcut?
Press the space bar to start, pause and resume, as long as you are not typing in one of the time boxes.