Online Stopwatch & Timer
Stopwatch with lap splits and countdown timer with audio alert. Includes Pomodoro presets. Precise millisecond timing right in your browser.
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How to use Online Stopwatch & Timer
The countdown timer runs a customisable timer from any hour, minute and second value down to zero, with audio and visual alerts. It supports pause/resume, resets, lap marking and multiple concurrent timers for use during cooking, exercise intervals, study sessions or any timed activity.
- Set the timer duration using hour, minute and second inputs.
- Click Start to begin the countdown.
- Pause and resume at any point, or reset to the original duration.
- An alert fires when the timer reaches zero.
Your data never leaves your device — 100% private processing.
Timer vs stopwatch vs countdown
A stopwatch counts up from zero; a countdown timer counts down from a set duration. This tool is a countdown timer. Stopwatches measure elapsed time during an activity; countdown timers enforce a time limit or remind you when a period has elapsed. For live event countdowns (days to a future date), use the Countdown tool.
Glossary
- Interval training
- Exercise structured as alternating high-intensity and rest periods, often timed precisely.
- Pomodoro
- A productivity technique using 25-minute work intervals followed by 5-minute breaks.
Related reading
Frequently Asked Questions
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Why use Online Stopwatch & Timer?
- Handles timezone conversions and DST automatically
- Supports date arithmetic across years and leap years
- ISO 8601 and human-readable output formats
- Works for historical and future dates with full accuracy
Common use cases
- Calculate how many days until a project deadline
- Find the day of the week for a date in the past
- Convert meeting times across different time zones
- Calculate age from a date of birth
- Add or subtract business days for contract terms
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