Online Stopwatch — Lap Timer, Fullscreen

A free stopwatch with laps, splits and fullscreen mode

Runs in your browser · nothing is uploaded

Laps

Press Lap (or the L key) while running to record splits.

Shortcuts

Space start / pause
L lap
R reset
F fullscreen

Settings and a running timer are stored in this browser only. A reload picks up where it left off.

What it is

A stopwatch for runs, presentations, cooking steps, lab work or anything else where you need to know how long something takes. It shows hundredths of a second, and while it is running you can press Lap to build a list of splits. The fastest and slowest laps are marked, so you can see at a glance how your pace changed. There is nothing to install and your times stay in your browser.

How to use

Press Start. The same button turns into Pause and Resume.
While it runs, press Lap. The table records the total time and the time since the previous lap, newest first.
Reset clears the time and all laps.
Use Fullscreen for big digits.
The copy button next to the laps exports number, lap time and total time as text.

Shortcuts: Space starts or pauses, L adds a lap, R resets and F toggles fullscreen. When a button or an input has focus, its own default behaviour takes priority.

How it works

Accuracy: elapsed time is the difference between the start timestamp and the current Date.now(), never a tick count. A late screen refresh cannot add error.
Display: hundredths are truncated, not rounded, so the screen never shows more time than has passed. After one hour the format becomes h:mm:ss.cc.
Pause: pausing stores the time so far; resuming adds from a fresh start timestamp.
Fastest and slowest: marked only when there are at least two laps with different lap times.
Storage: state and laps live in this browser’s localStorage.

Examples

Situation	Pressed at	Result
First lap	12.34 s	Lap 00:12.34, total 00:12.34
Second lap	30.00 s	Lap 00:17.66, total 00:30.00
Third lap	1 min 1.00 s	Lap 00:31.00, total 01:01.00
Pause and resume	Stop at 5 s, add 3 s later	Total 00:08.00

FAQ

Does the stopwatch slow down when I switch tabs?

No. It remembers the moment you pressed start and subtracts that from the current time on every screen update, so throttled background tabs do not cause drift. The elapsed time also shows in the tab title.

What is the difference between lap time and total time?

Total time is the elapsed time at the moment you press Lap. Lap time is the time since the previous lap. If you press Lap at 12.34 s and again at 30.00 s, the second lap time is 17.66 s.

Do I lose the laps if I reload?

No. The state and the laps are saved in your browser, and a running stopwatch carries on from its start timestamp after a reload. Private windows with blocked storage may not keep them.

How long can it run and how many laps are kept?

Up to ten days of elapsed time and 500 laps. The copy button next to the lap list gives you tab separated text you can paste straight into a spreadsheet.