For a free classroom timer, open the classroom timer, pick a preset from 1 to 60 minutes, press Full screen and then Start. A large ring shrinks as time runs out, turns amber when a fifth of the time is left and red at the end, and an alarm of your choice sounds at zero.
A visible countdown at the front of the room answers “how long do we have?” before anyone asks it. This guide walks through setting up our classroom timer on a projector or smart board, what each control does, how long to set for common activities, and how to make the timer work for students who rely on sight or sound alone. Everything runs in your browser, with no sign-up, and nothing you set is sent anywhere.
Set up the classroom timer in under a minute
- Open the page on the computer connected to the board. Go to the classroom timer on the machine that drives the projector, not on a phone.
- Pick a length. Tap one of the quick presets (1, 2, 3, 5, 10, 15, 20, 30, 45 or 60 minutes), or type any whole number of minutes from 1 to 60 and press Set.
- Choose the colors. Light, Dark or High contrast. High contrast shows white and yellow on black, which holds up on a washed-out projector.
- Test the sound. Pick an alarm and press Test sound while the room speakers are on.
- Go full screen and start. Press Full screen (or F), then Start (or the Space bar). Press Esc to leave full screen.
Once it’s running, you can control it from across the room with the laptop keyboard: Space starts and pauses, R resets to the length you set, and F toggles full screen. The +1 min button adds a minute at any point, which is handy when a group needs just a bit longer.
What the classroom timer does
These are the features on the live page today:
- A shrinking ring and large digits that scale up to fill the screen in full-screen mode.
- A color warning: the ring turns amber when a fifth of the time is left and red at the end. The words under the ring change as well, to “Almost done” and then “Time’s up,” so the warning doesn’t depend on color alone.
- Ten alarm sounds, including a soft chime, desk bell, gong and countdown pips, all generated in your browser. Hear them all on the countdown sounds page.
- A repeat option: the alarm can repeat until you stop it, for up to 1 minute, or play once if you untick the box.
- A system notification when time’s up, if you turn on “Notify me when time’s up.”
- Screen-awake support: while the timer runs, it asks the browser to keep the screen from dimming, where the browser supports it.
- Accurate timing in a background tab: the countdown is worked out from the device’s real clock, so switching to your slides or a video on a computer doesn’t throw it off.
The classroom timer stops at 60 minutes. For a longer exam, the main online timer runs for up to 24 hours and also has a full-screen view.
When the warning color appears
Because the amber warning starts when a fifth of the time remains, it always arrives at the same proportion of the activity. Here’s when it appears for each preset, worked out from that rule:
| Preset | Ring turns amber with | Ring turns amber after |
|---|---|---|
| 1 minute | 12 seconds left | 48 seconds |
| 2 minutes | 24 seconds left | 1 min 36 sec |
| 3 minutes | 36 seconds left | 2 min 24 sec |
| 5 minutes | 1 minute left | 4 minutes |
| 10 minutes | 2 minutes left | 8 minutes |
| 15 minutes | 3 minutes left | 12 minutes |
| 20 minutes | 4 minutes left | 16 minutes |
| 30 minutes | 6 minutes left | 24 minutes |
| 45 minutes | 9 minutes left | 36 minutes |
| 60 minutes | 12 minutes left | 48 minutes |
On a 45-minute test, that gives students a 9-minute heads-up to start checking their answers. If you’d like a different warning point, set the timer for the working time, then start a second, shorter countdown for the wrap-up.
How long to set for common activities
There’s no single right length, and your own class will tell you quickly what works. These are starting points that match the presets, so each one is a single tap:
- Transitions (1 to 3 minutes): tidying up, lining up, or moving between stations. A short, visible deadline keeps everyone moving together.
- Think time (1 to 2 minutes): quiet thinking before a pair or group discussion.
- Pair talk (3 to 5 minutes): a quick exchange before sharing with the class. The 5 minute timer opens ready to start.
- Warm-ups and exit tickets (5 to 10 minutes): a bell-ringer at the start or a short check at the end of class.
- Independent reading (10 to 20 minutes): the ring shows progress at a glance without anyone needing to read the clock.
- Group work (15 to 30 minutes): split it into stages and restart the timer for each, so groups know when to move on.
- Quizzes and tests (up to 60 minutes): show the full length so students can pace themselves.
For stations or rotations, run one countdown per round and reset between them. For focus blocks with breaks, the Pomodoro timer runs work and break periods back to back; our Pomodoro technique guide explains how the cycle works.
Accessibility: visual cues, sound and screens
A timer is only useful if everyone in the room can follow it. A few settings help:
- Working without sound. Set Alarm sound to “Silent (no sound)” for a quiet countdown, for example during a test. The ring, the color change and the “Almost done” and “Time’s up” text still show the state of the countdown, and the timer remembers the choice on that device.
- A gentler alarm. If a loud alert is too much for some students, choose a softer sound such as the soft chime, and untick the repeat option so it plays once.
- Color isn’t the only signal. Because the text under the ring changes too, students who can’t tell amber from red still get the warning.
- Contrast and glare. High contrast suits bright rooms and faint projectors; Dark is easier on the eyes in a dim room.
- Size. Full screen makes the digits as large as the display allows, which helps students at the back.
Some students find a countdown stressful rather than helpful. If that’s the case, a longer timer with no repeating alarm, or simply keeping the timer on your own screen, may suit them better. You know your students best.
Troubleshooting on a projector or phone
- No sound: browsers only play sound after you interact with the page, so press Start yourself rather than relying on autoplay. Check the room speakers, and on an iPhone, the silent switch.
- Screen went dark: some browsers ignore the request to keep the screen awake. Change the computer’s power settings for the lesson if it keeps happening.
- Using a phone: phones often pause web pages while the screen is locked, so the alarm may not sound until the screen is back on. Keep the screen on and the volume up.
- Nothing happens: the timer runs in your browser and needs JavaScript turned on.
Frequently asked questions
What is the best classroom timer to put on a projector?
Any timer with large digits and a full-screen view works. Our free classroom timer adds a shrinking ring, a color warning and ten alarm sounds, with no sign-up or download.
How do I make the timer fill the whole screen?
Press Full screen, or the F key, and the ring and digits scale up to fill the display. Press Esc to return to the normal page.
Can I use the classroom timer without sound?
Yes. Choose “Silent (no sound)” in the Alarm sound menu. The ring, the color change and the on-screen text still show how much time is left and when it’s up.
Can I set a classroom timer longer than an hour?
The classroom timer goes up to 60 minutes. For a longer exam, use the main online timer, which runs for up to 24 hours.
Does the timer keep running if I switch to my slides?
On a computer, yes. The countdown follows the real clock, so it stays accurate in a background tab and the alarm still sounds on time.