Online Stopwatch

How it works

Press Start to begin. Pause freezes the time exactly where it is and Resume picks up from there, so the time you spent paused is never counted. Reset returns everything to zero and clears the lap list. If you prefer the keyboard, Space starts and pauses, L records a lap, R resets and F goes fullscreen.

How to read lap and split times

Press Lap while the stopwatch is running to record a pass without stopping the clock. Each row shows two values: the lap time, which is that lap on its own, and the split time, which is the total elapsed when you pressed the button. Four laps of 1:30 read as lap times of 1:30 each and split times of 1:30, 3:00, 4:30 and 6:00. The newest lap sits at the top.

Once you have two or more laps, the fastest and slowest are labelled, so you can see at a glance whether you are holding your pace or fading. Lap times are worked out from the raw elapsed values rather than from the numbers on screen, so a long session with dozens of laps will not accumulate rounding errors. Times are shown to a hundredth of a second, which is as precise as a stopwatch started by hand can honestly claim to be: below that, you are timing your own reactions.

What an online stopwatch is good for

In sports it times laps of the track, lengths of the pool, interval repeats or a plank hold: leave the phone at the side of the lane and tap Lap on every pass. In the kitchen it answers the opposite question from a timer - not "tell me when ten minutes are up" but "how long has this dough been resting, and how long has the roast been in?"

For studying, it shows how long a practice SAT section, a speech or a presentation really takes, which is rarely what you guessed. Musicians use it to time a piece, or to find a tempo: count the beats for 15 seconds and multiply by four for beats per minute.

Accuracy and background tabs

The stopwatch measures against a steady clock that is independent of the time of day, so changing your system clock or crossing a daylight-saving boundary cannot add or remove time from a running measurement. Switching tabs stops the display updating but not the measurement; the moment you come back it catches up to the correct value. Refreshing the page keeps a running or paused stopwatch, along with its laps.

Frequently asked questions

Does the stopwatch keep running in a background tab?

Yes. It measures against a steady clock, so switching tabs stops the display updating but not the measurement. When you come back it catches up to the correct value.

What happens if I refresh the page?

A running or paused stopwatch is kept, along with its laps, so a refresh does not lose your time.

How do I record lap times?

Press Lap while the stopwatch is running, or press L. Each row shows that lap on its own and the total elapsed time; with two or more laps, the fastest and slowest are labelled.

Is an online stopwatch accurate enough for sports?

For training, yes: it shows hundredths of a second and does not drift. Like any hand-operated stopwatch, its limit is your reaction time at the start and the finish, around one to two tenths of a second.