Classroom timer

A classroom timer that's easy to read from across the room

Most online timers are built for one person at a desk. A classroom timer has a different job: thirty children need to see it at once, a teacher needs to start it in one tap while talking, and nobody should be startled when it ends. This one is built for that.

• Big, steady numbers. The countdown uses tabular figures, so the digits don't jump around as they change, and it gets bigger in full screen.
• A picture of time. Switch to a pie that shrinks toward 12, a sand timer that empties, or a bar. A picture works for children who can't read a countdown yet, and for anyone who'd rather not watch seconds tick.
• Several timers. Run up to four at once, each with its own name.
• Gentle endings. Choose a soft chime, a bell, quiet beeps or no sound. When time runs out the timer turns green and says Time's up, so the end is clear even with the sound off.
• It keeps good time. More on that below.

Ways teachers use a classroom timer

Timers work best as part of a routine: say what happens when the timer ends before you start it, and use the same sound every day. A visible countdown also helps children learn how long a minute feels, which is a real math skill: estimating time comes before measuring it.

Pie, sand, bar or numbers

The pie shows the time left as a colored wedge that shrinks toward 12, like a classroom visual timer. It fills the whole face at the start, whatever length you choose, so a 2-minute and a 20-minute timer both start full. The sand timer empties the top bulb into the bottom one. The bar drains from right to left, which fits well under slides. Numbers only is the classic big-digit countdown. Every view also shows the numbers, and screen readers hear the time left. For younger children, the visual timer page starts in pie view.

Background tabs and alarm limits

Browsers slow down web pages that aren't on screen to save battery. Chrome, for example, checks a hidden page's timers about once a second, and after a page has been hidden for five minutes it can check some of them only once a minute. A countdown that works by counting ticks ("subtract one second every second") falls behind when that happens, which is why some online timers end late after you switch to your slides.

The countdown uses an end timestamp and catches up when the page redraws. Background tabs, muted audio, screen locking and device sleep can delay or prevent the alarm. Keep the page open and the device awake when the end signal matters.

Multiple timers for stations and groups

Press Add timer to add a second, third or fourth countdown. Each has its own name, time and controls, and they run independently: start Group 1's timer, then Group 2's a minute later. On a wide screen, two or four timers sit in a grid and three sit in a row. Remove any timer with its X button. In full screen with one timer, the countdown fills most of the screen; with several, each one stays readable.

Keyboard and accessibility

• Space starts and pauses the first timer when nothing else is selected, so you can control it from the keyboard, or from a presentation clicker if yours sends the space bar.
• Every control is a labeled button at least 44 pixels high, for touchscreens and smartboards.
• Screen readers can read the time left and hear "time's up" when a timer finishes.
• The end of a timer is shown by color, words and (optionally) sound, never by color alone, and the short pulse animation is skipped when your device asks for reduced motion.

Setting up the timer before class

A minute of setup saves interruptions later. Open the timer on the projector or board before students arrive, pick the view you'll use all day, and choose a sound. Name the timer after the next activity, so the screen tells students what's coming. If you use stations, add a timer per group now and name each one. Your view and sound choices are remembered on this device, so tomorrow it opens the same way.

Quick timers

Already know how long you need? These pages open with the time set: 1 minute, 2 minutes, 3 minutes, 5 minutes, 10 minutes, 15 minutes, 20 minutes, 30 minutes and 1 hour.

Teaching time with timers

A timer is a good way into telling time. Ask, "The timer says 10 minutes. It's 1:15 now. What time will it be when it rings?" Children can check on the interactive clock or with the elapsed time calculator. For practice reading clocks, try the telling time game.

Before a group activity, run a short countdown to confirm the chosen sound is audible and the screen is easy to see. Explain what happens at the end, and let participants know how to ask for more time. Choose a duration for the task rather than treating a countdown as a measure of ability.