🧮 Calculators
Stopwatch & Countdown Timer
A full-featured online stopwatch with lap recording, plus a countdown timer with alarm. Works entirely in your browser.
00:00.00
Advertisement
Free Online Stopwatch & Countdown Timer
Our free online stopwatch and countdown timer give you everything you need for precise time tracking right in your browser — no app download, no login, no ads interrupting your focus. Whether you're timing a workout, cooking, a presentation, a test, or a race, this tool has you covered.
The stopwatch supports lap recording so you can track multiple intervals in sequence — great for running, swimming or interval training. The countdown timer lets you set any time from seconds to hours and plays an alarm sound when it reaches zero. Both tools work when the browser tab is in the background.
⏱ Precision Stopwatch
Counts to milliseconds. Record multiple laps with split times.
⏳ Countdown Timer
Set any duration — alarm sounds when time is up.
📋 Lap Recording
Track each lap time and total elapsed time simultaneously.
🔔 Audio Alarm
Countdown plays an audible alert when it reaches zero.
How to Use the Stopwatch & Timer
1
Choose your mode
Click the Stopwatch tab to count up, or the Countdown tab to count down from a set time.
2
Start timing
Press Start to begin. The timer runs even if you switch to another browser tab.
3
Record laps (stopwatch)
Press Lap while the stopwatch is running to record a split time. All laps are shown below with their individual and cumulative times.
4
Reset when done
Press Stop then Reset to clear the timer and start fresh for the next session.
Frequently Asked Questions
Does the stopwatch work if I switch tabs?
Yes — the timer continues running in the background when you switch to another tab or minimise your browser. It uses JavaScript's performance.now() API for accurate timing that isn't affected by browser throttling. However, the display will only update visually when you return to the tab.
How accurate is this stopwatch?
The stopwatch is accurate to milliseconds using the browser's high-resolution timer (performance.now()). For everyday use — sports, cooking, presentations — it is perfectly accurate. For scientific or laboratory timing requiring microsecond precision, a dedicated hardware timer would be more appropriate.
Can I use this stopwatch on my phone?
Yes — the tool is fully mobile-friendly and works on all smartphones and tablets. Open it in Chrome, Safari or any modern browser on your phone and it behaves exactly like the desktop version. The large buttons are designed for easy tapping on touchscreens.
Does the countdown timer alarm work?
Yes — when the countdown reaches zero, it plays an audible alarm sound. Note that some browsers require a user interaction (like clicking Start) before they allow audio playback, which is why the alarm only triggers after you've actively started the timer rather than on page load.
Is there a maximum time limit?
The stopwatch can count indefinitely — there is no upper limit. The countdown timer supports any duration from 1 second up to 99 hours 59 minutes 59 seconds, which should be more than enough for any practical use.