A free online classroom timer built for teachers — fullscreen mode projects large, readable digits on any display; the Multiple Timers tab manages different student groups simultaneously; and labels tell students exactly what each countdown is for. No account required, no ads, works fully offline.
How Teachers Use Polytimer
Open Polytimer on your teaching device and connect to the projector.
Enter the activity duration in the Countdown tab and label it (e.g. "Group Work", "Quiz", "Exit Ticket").
Press F or click the Fullscreen button — large digits fill the screen, visible from every seat.
Press play or hit Space to start. The progress bar and countdown update in real time.
For multiple groups, use the Multiple Timers tab and add one timer per group.
Classroom Timer Presets by Activity
1 Minute — quick think-pair-share, settle-down signal, transition between activities
45 Minutes — full class period in many school systems
Features for Teachers
Fullscreen mode — large digits visible from the back of any classroom; press F to toggle
Multiple Timers — run separate countdowns for different groups or stations simultaneously
Labels — name each timer so students know what each countdown is for
End Time display — shows the exact clock time the activity ends (e.g. "Ends at 2:15 PM")
Silent mode — mute the alarm for test and exam conditions while keeping the visual countdown
Works offline — continues running even if school WiFi drops mid-lesson
No sign-up required — open polytimer.com and start immediately
Using Multiple Timers for Group Work
For differentiated group activities where each group has a different time allocation, use the Multiple Timers tab:
Switch to the Multiple tab.
Add one timer per group — label each with the group name or activity (e.g. "Group A — 15 min", "Group B — 10 min").
Start each timer when that group begins their task.
Each alarms independently when that group's time is up.
Frequently Asked Questions
How do I display a classroom timer on a projector?
Click the Fullscreen button or press F to enter fullscreen mode. Large, high-contrast digits fill the entire screen — visible from the back of a classroom when projected. The timer continues running in fullscreen and the alarm plays at the end of the period.
What is the best online timer for teachers?
Polytimer is designed for classroom use: fullscreen projects large digits on any display; Multiple Timers lets you run group timers simultaneously; labels identify each activity; alarm sounds clearly when time is up. No account, no ads, works offline.
Can I run a silent countdown timer for a classroom test?
Yes. Set your test duration, enable Fullscreen so students see the countdown, and mute the alarm in the Sounds drawer for a completely silent visual countdown.
How do I set different timers for different groups?
Use the Multiple Timers tab. Add one timer per group, label each with the group name, and start them simultaneously or offset. Each alarms independently when that group's time is up.
Can the classroom timer work without internet?
Yes. Polytimer is a Progressive Web App that works fully offline once loaded. Open it at the start of class — it continues working even if the school WiFi drops. You can add it to your device's home screen for fast access.
How do I show students how much time is left?
Use Fullscreen mode to project a large countdown. The progress bar shrinks visually as time runs out, giving students a clear visual cue. Enable the End Time toggle to also show the exact clock time the activity ends.