Stopwatch & Timer
Precision stopwatch with laps and countdown timer with audio alert
What is Stopwatch & Timer?
A stopwatch measures elapsed time from a start point, while a countdown timer counts down from a set duration to zero. Both are essential timing tools used in sports training, cooking, studying, presentations, workouts, laboratory experiments, and everyday task management. Having a reliable, precise digital stopwatch and timer available instantly in a browser tab eliminates the need for a physical stopwatch or a separate app.
Timing tools are deceptively important for productivity. The Pomodoro Technique — a popular productivity method — uses timed 25-minute work sessions separated by 5-minute breaks. Sports coaches use lap timers to track individual sprint times across intervals. Developers use timers to benchmark code performance. Chefs use countdown timers to track cooking times. Teachers use timers for timed tests.
Altairys's Stopwatch & Timer combines both functions in a single clean interface. The stopwatch records lap times with each press of the lap button, stores a full session log, and displays average and best lap times. The countdown timer allows any duration to be set and triggers an alert when it reaches zero. Both tools display time to millisecond precision and work even if you switch to another browser tab.
How to Use Stopwatch & Timer
- Start the stopwatch
Click Start to begin timing. The display updates in real time to the millisecond.
- Record lap times
Press Lap to record the current split time without stopping the overall timer.
- Stop and review
Press Stop when done. Review all lap times, your best lap, and average lap time.
- Use countdown timer
Switch to Timer mode, set a duration, and get an alert when the countdown reaches zero.
Key Benefits
Displays hours, minutes, seconds, and milliseconds for accurate timing.
Record multiple lap times and see the best, worst, and average lap in the session log.
The countdown timer triggers an audio and visual alert when it reaches zero.
Continues timing accurately even when you switch to other browser tabs.
Frequently Asked Questions
Browser timers use the performance.now() API which has sub-millisecond resolution. Displayed accuracy is to the nearest 10ms. For scientific purposes, a dedicated hardware timer is more reliable, but for sports, cooking, and productivity use cases, browser precision is more than adequate.
No. The timer uses the system clock for elapsed time calculation, so it continues running accurately even when the browser tab is in the background.
Yes. You can copy all lap times to the clipboard as a formatted table, or save the session as a text file for later reference.
The Pomodoro Technique is a time management method where you work for 25 minutes (one "pomodoro"), then take a 5-minute break. After four pomodoros, take a longer 15-30 minute break. Our timer is perfect for this method.