A stopwatch is for a length you do not know yet
Use an online stopwatch when the end is a fact you are trying to learn: how long the task really took, how long the lap was, how long you talked before you noticed. A timer is the other tool. It starts from a length you already chose and runs down to zero. If you know you have 15 minutes, open the 15 minute timer and do not watch a stopwatch hoping you will stop yourself. If you do not know, this page is the honest one.
Start begins at zero, or resumes after a pause without losing the time you already banked. Lap records the split since the previous lap and the total, and it only works while the clock is running. The list keeps the latest laps. Reset clears everything, including laps, so do not press it when you only wanted to pause. Space starts and pauses, L marks a lap, R resets, and F fills the screen.
Background tabs and what they cannot do
The elapsed time is computed from the moment you started, plus any time you banked during pauses. Looking at another window does not freeze a stopwatch on a computer that stays awake, because the page reads the clock when it draws. A sleeping laptop or a phone that suspends the browser is a different story. Do not use this as the official clock of a race, a lab, or an exam. Those have their own timing. This is a clear counter for practice, chores, and talks.
Hundredths of a second are shown so laps are easy to compare. They are not a claim of laboratory accuracy. The display follows your device. If you need an alarm at a known length, switch to a timer. The stopwatch does not ring at a target you forgot to set. That silence is useful: it will not stop you in the middle of measuring.
- Talks: learn the real length, then pick a timer preset next time.
- Workouts: lap each set so the rest is visible.
- Chores: measure once before you promise a duration.
- Reset only when you want zero. Pause when you want to keep the total.
After you know the number
When the stopwatch has taught you the length, move to a preset if it is a round number you will repeat: 5, 10, 20, 25, or 30 minutes are all separate pages. Odd lengths can be typed on the timer. A date in the future is still not a stopwatch problem. Count the days on days between dates, or open the countdown if you want a live clock until that moment. Nothing on this page is stored on a server. A reload starts at zero again.