Online Stopwatch
What is Online Stopwatch
This online stopwatch counts up from zero with hundredth-of-a-second precision, so you can time anything without hunting for a physical stopwatch. Press start, record laps as you go and read the split and total time for each one. It runs entirely in your browser, keeps counting accurately even when the tab is in the background, and needs no download or account.
How to use
- Press Start to begin timing from zero.
- Press Lap to mark a split without stopping the clock. Each lap shows its own time and the running total.
- Press Pause to stop, then Resume to keep going from where you left off.
- Press Reset to clear the time and all laps. You can also use Space to start or pause, L for a lap and R to reset.
When to use it
Need to time a workout, a presentation rehearsal or how long the pasta has been boiling? Press Start and read the clock to the hundredth of a second. Timing intervals or repeats, tap Lap on each one: run 400 meters four times and you get four split times plus the total, with the fastest and slowest laps marked so you can compare them at a glance.
Frequently asked questions
How accurate is this stopwatch?
It measures elapsed time from your device's high-resolution clock and shows hundredths of a second. The reading stays accurate even if the browser tab is in the background, since the total is recomputed from the real clock rather than counted frame by frame. The limit in practice is your own reaction time when you press the buttons.
What is a lap time?
A lap, or split, is the time recorded each time you press the Lap button while the stopwatch runs. The clock keeps going, so you get the time for that segment and the running total side by side. It is handy for timing repeated efforts like laps of a track or sets of an exercise.
Does the timer keep running if I switch tabs?
Yes. Elapsed time is measured against your device clock, so switching tabs or locking the screen does not lose time. When you come back the display catches up to the correct value right away.
Can I put this stopwatch on my own website?
Yes, for free. Open 'Embed this tool' just below the stopwatch, copy the iframe code and paste it into your page. The widget is self-contained and needs no install. Add ?theme=dark or ?theme=light to the embed URL to match your site.
Related tools
Aspect Ratio Calculator
Calculate aspect ratios, find a missing width or height, and resize images or video while keeping the same proportions. Free and instant.
Base64 Decoder
Decode Base64 strings to plain text instantly in your browser. Supports full Unicode output including emojis. Free online Base64 decoder.
Base64 Encoder
Encode any text to Base64 instantly in your browser. Supports Unicode, emojis and special characters. Free online Base64 encoder.