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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.

  1. Set the timer duration using hour, minute and second inputs.
  2. Click Start to begin the countdown.
  3. Pause and resume at any point, or reset to the original duration.
  4. An alert fires when the timer reaches zero.

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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.

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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

Related Date & Time

Explore all Date & Time.