Online Stopwatch
A free, accurate online stopwatch with start, stop, lap and reset. Records lap and split times with millisecond precision. Runs in your browser — no install.
Last reviewed by the Radiatus Cloud team
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An accurate online stopwatch
A stopwatch you can genuinely rely on, with all the features that actually matter: start, stop, lap and reset, recording lap and split times accurately as you go. This free online stopwatch works entirely in your browser, with nothing to install and no account required, so it is ready the moment you need it.
Why an accurate browser stopwatch
A stopwatch is only worth using if it keeps accurate time, and a browser-based one, implemented properly, does exactly that without needing a physical device or an app installed on your phone. Lap and split recording lets you time individual intervals within a longer session, marking each one without ever stopping the overall clock, which is what separates a real stopwatch from a simple timer. That covers everything from timing a training run to a cooking step to the length of a presentation, and because it lives in the browser it is always available, on any device you happen to have, immediately.
Always available
It runs entirely in your browser, so nothing you enter is uploaded and it works without an account, keeping everything on your own machine and available on any device immediately.
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Frequently Asked Questions
Is an online stopwatch accurate?
Yes. Implemented properly, a browser stopwatch keeps precise time, more than sufficient for timing runs, workouts, cooking and everyday needs.
What is the difference between lap and split?
A lap records the time of each individual segment; a split records the total elapsed at each mark. Both are captured without stopping the clock.
Do I need to install anything?
No. It runs in your browser with nothing to install and no account, available immediately on any device.
Can I reset it?
Yes. Start, stop, lap and reset are all available, so you can clear it and time again as often as you like.
Is my data uploaded?
No. The stopwatch runs entirely in your browser.
Privacy & Security
All processing happens locally in your browser — nothing is uploaded.
How to Use
Press Start to begin timing. Use Lap to record splits and Reset to clear.
Disclaimer: This tool is provided "as is" without warranty of any kind. Results are for educational and utility purposes.
Related Tools
User Agent Parser
UtilityParse a User-Agent string into browser, engine, operating system and device. Explains why UA strings are unreliable and what to use instead.
QR Code Generator
UtilityGenerate QR codes for URLs, text, Wi-Fi and contact details. Adjustable error correction and size, produced entirely in your browser.
Credit Card Validator
UtilityValidate a card number with the Luhn algorithm and identify the issuing network from its prefix. Runs locally, nothing is transmitted.