How the stopwatch works
Last updated 10 November 2026
A stopwatch measures how long something takes, counting up from zero. People use one to time a run, a swim, a speech, a recipe step, a work task or a game. This one is free, has no sign-up and works on a phone or a computer.
Press Start to begin, Stop to pause the clock, and Resume to carry on from where it stopped. Press Lap while it is running to mark a point without stopping it. Reset clears the time and the laps.
How it works
The stopwatch does not count ticks. When you press Start it remembers the moment on your device's clock. Every redraw works out the time that has passed since then and adds any time banked from earlier runs. Pausing banks the time so far, and resuming starts a fresh measurement.
For example, if the clock showed 1:05.4 when you stopped it, and you resumed and ten seconds later looked again, it would show 0:01:15.4. A slow or throttled tab cannot lose time, because nothing is added up tick by tick.
Worked example
Reading the lap list. Say you pressed Lap three times while a run was in progress:
- Lap 1: split 0:00:31.2, total 0:00:31.2.
- Lap 2: split 0:00:47.7, total 0:01:18.9 (slowest).
- Lap 3: split 0:00:25.4, total 0:01:44.3 (fastest).
Split and total
The total is the time since you pressed Start, so it keeps growing from lap to lap. The split is the time for just that lap, which is the difference between this lap's total and the one before. Splits show whether you are speeding up or slowing down, and totals show how long the whole effort has taken.
Fastest and slowest
Once you have three or more laps, the quickest split is marked Fastest and the longest is marked Slowest. If every lap is exactly the same length, nothing is marked.
Accessibility
All the buttons can be used with the keyboard, and they are large enough to tap with a thumb. The running clock is not read aloud every tenth of a second. Instead, a screen reader hears a short message when you start, stop, record a lap and reset, including the lap number and its split time.
Getting a fair result
The stopwatch shows tenths of a second, but your reaction time is the limit on accuracy. A person pressing a button is usually a tenth or two late at each end. That matters for a short sprint and hardly matters for a long task. It is fine for training, cooking and meetings. It is not an official timing system.
- Use laps for repeated efforts, such as each length of a pool.
- Stop the clock before you read or copy the time.
- Write down your times before you reset.
Other clock tools
To count down instead of up, use the timer. To count down to a date, use the countdown timer. To add up several times, use the time calculator.
Privacy
The stopwatch runs in your browser. Your times and laps are not stored or sent anywhere, and the page asks for no permissions.
Things to watch
- Keep the tab open while timing. If your phone locks or the browser is closed, the page may stop.
- Reset removes the laps, so note them down first.
Like every tool on MoneyMzansi, this one works in your browser with no account and no upload.