What is the Online Stopwatch?
The online stopwatch measures elapsed time to the hundredth of a second. Press Lap to record split times for each round, then copy the lap list to a spreadsheet. The Space bar starts and pauses; L records a lap.
For a countdown that rings an alarm use the Online Timer; to add up hours worked over a week use the Working Hours Calculator.
How to use the Online Stopwatch
- Press Start (or the Space bar).
- Press Lap (or L) to record a split.
- Press Pause to stop and Reset to clear.
- Copy lap times if needed.
Example
Timing four 400 m laps: Lap 1 01:18.42, Lap 2 01:21.05, Lap 3 01:20.37, Lap 4 01:16.90, total 05:16.74.
Lap time vs split time
A lap time is the time for one lap alone; a split time is the total time since the start at that moment. The stopwatch shows both, so you can see whether you are speeding up or slowing down.
Uses
- Running, swimming and cycling training
- Science experiments in school
- Timing speeches and presentations
- Measuring how long tasks take at work
More free date and time tools
Planning around dates usually needs more than one answer. These related tools work the same way, instantly in your browser and free:
- Days until any date: count down to an exam, trip or deadline.
- Date calculator: add or subtract days, weeks, months or business days.
- Date difference calculator: the exact time between two dates.
- Age calculator: your exact age in years, months and days.
- Time zone converter: the same moment in Pakistan, the Gulf, the UK and the USA.
- Online timer: a countdown with an alarm sound.
Frequently asked questions
How accurate is the online stopwatch?
It uses your device's high-resolution clock and is accurate to about a hundredth of a second.
Does it keep running in another tab?
Yes. Elapsed time is based on the clock, so it stays correct.
What are the keyboard shortcuts?
Space to start or pause, L for lap, R to reset.
Can I save lap times?
Use the copy button to paste them anywhere.
Does it work on mobile?
Yes, with large touch buttons.
Is the Online Stopwatch free to use?
Yes. The Online Stopwatch on Custom Converter is completely free, with no sign-up, no daily limit and no watermark.
Does the Online Stopwatch work on mobile phones?
Yes. It is built mobile-first and works on Android phones, iPhones, tablets and computers in any modern browser, with no app to install.