Stopwatch
Time something to the hundredth of a second, with laps. Entirely in your browser.
Runs entirely in your browser. Nothing is uploaded, logged or stored.
00:00.00
| # | Lap | Total |
|---|
Start, stop, and take a lap whenever something is worth marking. The elapsed time is shown to the hundredth of a second, and each lap keeps both its own duration and the total up to that point.
How it works
The elapsed time is the difference between now and the moment you pressed start, read fresh on every frame. Nothing is accumulated, so nothing drifts: stopping and starting again carries the time already run and leaves the pause out.
A lap records the total at that instant. The lap time shown beside it is the gap since the previous lap, which is the number you usually want and the one a stopwatch that only kept totals makes you work out yourself.
The reading uses a clock that cannot be adjusted while the page is open, so a device that syncs its time mid-measurement — or crosses into daylight saving — does not move the result.
Examples
| Case | Input | Result |
|---|---|---|
| A lap keeps both numbers | Lap at 01:12.40, next at 02:30.05 | Lap 2: 01:17.65, total 02:30.05 |
| Under an hour the hours are not shown | 4 minutes 5 seconds | 04:05.00 |
| Past an hour they appear | 1 hour 4 minutes 5 seconds | 1:04:05.00 |
Frequently asked questions
How accurate is it?
Accurate enough for anything you are timing by hand. The limit is not the clock — it is the gap between the thing happening and your finger reaching the button, which is a couple of tenths of a second at best. The hundredths are shown because a stopwatch that hid them would round two close laps to the same number.
Does it keep counting in a background tab?
Yes. The display stops updating, because browsers stop redrawing a tab you cannot see, but the elapsed time is worked out from when you started rather than from how many times the page has redrawn. Come back and it is correct.
Are my laps saved?
No. Nothing leaves the page and nothing is kept: closing the tab or reloading loses them. Copy them out before you go if they matter.
Why does resetting not ask me to confirm?
Because a stopwatch that asked would be slower to use every single time in order to help on the rare one. Reset is only offered while the watch is stopped, which is the point at which you have already decided.
Good to know
- The clock is read from your device, not counted. A timer that added up its own ticks drifts, and browsers slow those ticks right down in a tab you are not looking at — so a five minute timer left in the background would come back minutes late. Every display here is computed from the time it started, which makes switching tabs and locking the screen harmless.
- Nothing is stored and nothing is sent. Close the page and the timer is gone, which is also why a share link carries the settings and never a timer in progress.