Online Stopwatch
Precise stopwatch with lap times. Countdown timer with alarm. Works offline as a Progressive Web App.
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About Online Stopwatch & Countdown Timer
Precision stopwatch with split/lap time recording. Countdown timer with audio alarm. Supports Pomodoro technique presets (25 min work, 5 min break). Works offline — pure JavaScript, no server required.
A precise online stopwatch and countdown timer is essential for students, athletes, cooks, and productivity practitioners. The Pomodoro Technique — 25 minutes focused work, 5 minute break — is one of the most evidence-backed productivity methods. This tool supports Pomodoro presets, lap timing for athletes, and custom countdowns for any duration.
How to use
- Enter a value and pick your source and target units — the conversion updates instantly.
- Double-check the unit abbreviations shown, since similarly-named units sometimes use different base definitions.
- Use the swap or reverse option if available to quickly flip the conversion direction.
- Chain into a related converter below if your task needs a second conversion step.
- All conversions are computed in your browser using standard, precise conversion factors.
Tool details
⚡ Next step — complete your workflow
Frequently asked questions
Is this stopwatch accurate?
Uses browsers performance.now() API which provides millisecond precision. Accuracy is limited by browser tab throttling — for professional timing, use a hardware stopwatch.
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