SolutionsCase StudiesAI ToolsResourcesAboutContact
Get Your Free AI Automation Audit Book a Free 30-Minute Strategy Call

Classroom Timer, Stopwatch & Pomodoro

A very large countdown timer with one-tap presets from 1 to 60 minutes, plus a stopwatch and a Pomodoro timer (25 minutes of work, 5 minutes of break, a longer break every fourth round). Press full screen to show it on a projector; an optional chime sounds at zero.

Free, no signupNo daily limitRuns in your browser - nothing you enter is uploadedUpdated

Ready
05:00

Keys: Space start / pause · R reset · F full screen

Using it in class and in exams

  • Projector first. Press Full screen and the digits fill the screen, readable from the back of a classroom. Esc leaves full screen.
  • Timed tasks. One-tap presets for the usual lengths: 1 minute for a quick-fire question, 5 for think-pair-share, 10-15 for a task, 30-60 for a test section.
  • Exams. Set the exact length with the custom fields (up to 24 hours), go full screen and start. Keep the laptop plugged in and stop it sleeping.
  • Transitions. The progress bar shows how much time has gone, which younger students read faster than numbers.
  • Focus sessions. The Pomodoro tab runs 25 minutes of work and 5 of rest, with a 15-minute break after every fourth round, and moves to the next phase on its own.

The chime is off until you tick it: browsers only allow a page to play sound after you have interacted with it, and a silent default suits exam rooms.

Worked example: why it does not drift

When you start a 5-minute countdown at 10:00:00, the timer stores one number - the moment it should reach zero, 10:05:00 - and every screen update shows end time − now.

start 10:00:00 → end = 10:05:00 you switch tabs; the browser slows the page down you come back at 10:02:00 shown: 10:05:00 − 10:02:00 = 03:00 (not "the ticks it managed to count")

A full Pomodoro cycle with the default settings is 4 × 25 minutes of work, 3 × 5 minutes of short break and one 15-minute long break: 130 minutes.

What this calculator does not do

  • If the computer goes to sleep the timer cannot chime until it wakes up, although the time shown is then correct.
  • The longest countdown is 24 hours.
  • Some phone browsers do not allow full screen for part of a page.

Frequently asked questions

Will the timer stay accurate if I switch tabs?
Yes. The remaining time is worked out from the clock each time the screen updates, not by counting ticks, so it does not drift when the browser slows down a background tab. When you come back the display shows the correct time.
How do I show the timer on a projector?
Press "Full screen" (or the F key). The digits fill the screen; press Esc to leave full screen.
Does it make a sound at the end?
Only if you turn on "Chime at zero". Browsers only allow sound after you have interacted with the page, so the chime is enabled when you tick the box.
How does the Pomodoro timer work?
It alternates 25 minutes of focused work with 5-minute breaks, and gives a 15-minute break after every fourth work round. You can change all three lengths.
What keyboard shortcuts are there?
Space starts or pauses, R resets and F toggles full screen, as long as you are not typing in a box.
Can I use it for exams?
Yes. Set a custom time, go full screen and start it. For long exams keep the device plugged in and stop it from sleeping, so the screen stays on.

Related free tools

Random Name Picker WheelSpin a wheel of names, roll dice, flip a coin or draw random numbers - fairly.
Easy GraderA printable chart of percentage and letter grade for every score on a test.
Hours CalculatorWeekly time card with breaks and pay, time sums and time between two times.
Final Grade CalculatorThe score you need on the final to reach your target grade, plus a what-if table.

Step-by-step guide: How to use the Pomodoro technique and a classroom timer →

Built and checked by Taimur Hassan Siddiqui, who has more than ten years in computer-science education. The formulas on this page are covered by an automated test suite, and the worked example on this page is one of its cases. Last updated 7 October 2026.