Classroom Stopwatch
A free online stopwatch for the classroom that counts up from zero and records lap times, with digits big enough to read from the back of the room. Use it when you want to know how long something took — a countdown timer is the tool for the other way round.
- No signup
- Nothing to install
- Free forever
00:00.00
Stopped at 0 seconds
How teachers use a stopwatch in class
A stopwatch answers a different question from a timer. A timer says how long is left; a stopwatch says how long it took. That makes it the tool for anything you want to measure and then beat — which is most of what makes practice feel like a game rather than a chore.
The lap button is what turns it into a maths lesson. Children reading times off the board and comparing them are doing real work with decimals and units, on numbers they generated themselves and therefore care about.
- Timing how long the class takes to line up, then beating it tomorrow
- Times tables or spelling sprints, where the time is the score
- PE — running, relays, circuits, with a lap per child or per team
- Science: how long a candle burns, how long ice takes to melt
- Reading fluency checks over a set passage
- Timing how long a transition really takes, when you suspect it is longer than it feels
Laps, and what to do with them
Each lap records the time on the clock and the gap since the previous lap, so a relay gives you both the running total and each leg on its own. The quickest and slowest are marked, which is usually the first thing a class wants to know.
A word of care with named times on a board: comparing children against each other publicly helps the fast ones and few others. Timing the whole class against its own record, or a child against their own previous time, gets the same energy without the cost.
Stopwatch or countdown timer?
Use the stopwatch when the end is unknown and the elapsed time is the point — a race, a challenge, an experiment. Use the classroom timer when the end is fixed and the class needs to see how long is left — a five-minute starter, ten minutes of writing, two minutes to tidy up.
Most lessons want the timer. The stopwatch earns its place in PE, in science, and in any activity where "how fast can we do this?" is the motivation.
Frequently asked questions
What is the difference between this and the classroom timer?
The stopwatch counts up from zero and tells you how long something took. The classroom timer counts down from a time you set and tells the class how long is left. For a timed task, use the timer; for a race or a challenge, use the stopwatch.
Does it record lap times?
Yes. Press Lap while it is running and it records both the time on the clock and the length of that lap on its own. The fastest and slowest laps are highlighted once you have more than one.
How accurate is it?
It reads from your device clock rather than counting frames, so it stays accurate to a hundredth of a second even if the tab is in the background or the board goes to sleep and wakes up.
Can I use the keyboard?
Yes. The space bar starts and stops it, which is quicker than reaching for a board when you are stood at the other end of the hall with a laptop.
Is it free?
Completely. No account, no signup, no adverts, and no limit on how often you use it.