Simple, Accurate, and Free Online Stopwatch
iStopwatch is a free and simple online stopwatch that allows you to measure time instantly in your web browser. Whether you need a stopwatch for workouts, studying, productivity tracking, cooking, or everyday tasks, this tool gives you a fast and reliable way to track time with precision — down to the millisecond.
Unlike traditional stopwatch devices or complicated apps, iStopwatch works directly in your browser on desktop, tablet, or phone. You don't need to download any software, create an account, or install additional tools. Just open the page and press Start.
How to Use the Online Stopwatch
Start – begin measuring time from zero. Lap – record a split without stopping the clock, so you can compare individual segments. Stop – pause the timer while keeping the elapsed time on screen. Reset – clear the time, laps, and start again from scratch.
Lap Times Explained
Each time you press Lap, the stopwatch records the time since your previous lap alongside the total elapsed time. Your fastest lap is highlighted in green and your slowest in red, making it easy to spot pacing trends during a workout, run, or study sprint.
Keyboard Shortcuts
For faster control without reaching for the mouse, use Space to start or stop, L to record a lap, and R to reset the stopwatch.
Common Uses for a Stopwatch
Runners and athletes use it to time laps and intervals. Teachers and students use it for timed tests and presentations. Cooks use it to track multi-step recipes. Coaches use it to run structured practice drills, and remote teams use it to time stand-ups and Pomodoro-style focus sessions.
Frequently Asked Questions
Is iStopwatch free to use?
Yes. The stopwatch is completely free and accessible to anyone, with no sign-up or account required.
Do I need to install software?
No installation is required. The stopwatch runs directly in your web browser on any device with an internet connection.
Is the stopwatch accurate?
Yes. The timer uses your device's system clock to measure time with high precision, updating in real time to the millisecond.
Can I use the stopwatch on my phone?
Yes. iStopwatch is fully responsive and works the same way on mobile browsers as it does on desktop.
More Free Time Tools
Looking for something else? Try our countdown timer, Tabata / interval timer, world clock and time zone converter, or date calculator.