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Stopwatch & Timer

Stopwatch, countdown and Pomodoro

A precise stopwatch with laps, a countdown timer with alerts and a Pomodoro focus timer, all in your browser.

How to use Stopwatch & Timer

  1. On Stopwatch, press Start, then Lap to record laps and Stop to pause. Resume carries on from where you stopped, and Reset clears everything.
  2. On Timer, set hours, minutes and seconds (or pick a preset) and press Start timer. Start more than one to run several timers side by side.
  3. On Pomodoro, set the focus, short-break and long-break lengths and how many focus sessions come before a long break, then press Start. Turn on Start the next session automatically to roll from one session into the next.
  4. Under Timer and Pomodoro, choose how you want to be told when time is up: a beep, a browser notification, or both. The text bar at the top always announces it too.
  5. Keyboard: Space starts or stops, L records a lap, R resets. They are ignored while you are typing in a field.

How it works

Every clock stores timestamps from performance.now(), the browser’s monotonic clock, and works out the time shown by subtracting them. The screen refreshes on a short interval, but the interval is only for drawing: if the tab sleeps or is throttled in the background, the next refresh still shows the exact time. The stopwatch updates about 20 times a second and shows centiseconds; with reduced motion turned on in your system it updates once a second and hides centiseconds while running. Lap time is the time since the previous lap, split is the total at that lap, and the fastest and slowest laps are marked once there are two or more. Countdowns are rounded up, so 00:01 stays until the last instant. When a timer or Pomodoro phase ends, the page announces it in a polite live region, plays three short beeps with the Web Audio API, and shows a notification only if you have already granted permission. While a timer or Pomodoro is running, the countdown also appears in the browser tab title. Everything runs in your browser.

Limits

  • A timer can be up to 99 hours 59 minutes 59 seconds. Pomodoro focus can be 1–180 minutes, short break 1–60, long break 1–120, and 1–12 focus sessions before a long break.
  • Timers, laps and sessions live in the page only. Reloading or closing the tab resets them; only your Timer and Pomodoro settings can go in a share link.
  • Browsers may not play sound or allow notifications until you have clicked something on the page, and some mobile browsers block page notifications entirely. The on-screen announcement always works.
  • A sleeping computer or a heavily throttled tab can only alert once it wakes up, though the time shown is then correct.
  • Time comes from the system clock source of your browser; it is accurate to about a millisecond but is not an official timing instrument.

Privacy

Nothing is sent anywhere and nothing is stored on your device. Copy share link puts only your Timer and Pomodoro settings (lengths and options) in the link’s # fragment, which browsers do not send to servers. Laps and running timers are never included.

Frequently asked questions

Does the stopwatch keep time if I switch tabs?

Yes. Time is calculated from timestamps, not by counting refreshes, so background throttling does not make it run slow.

Why did I not hear the beep?

Browsers only allow sound after you have interacted with the page, and the beep is switched off if Play a beep is unticked. Starting a timer by clicking Start counts as interaction.

How do I get notifications?

Tick Show a browser notification and allow the permission prompt. The page never asks on its own, and if you decline nothing changes except the notification.

What is the difference between lap and split?

Lap is how long that lap took. Split is the total elapsed time when you pressed Lap.

How does the Pomodoro cycle work?

Focus, then a short break, repeating; after every set number of focus sessions (4 by default) the break is the long one. Skip jumps to the next phase.

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