45 Minute Timer
A free 45 minute countdown timer. Common uses: a class period, a gym session, a half of football, and the standard ultradian rest cycle.
What is a 45 minute timer used for?
- ✓School and university class periods
- ✓Study and revision sessions
- ✓Focused work blocks
- ✓Workout sessions
How to use this timer
- 1Start the countdown
The timer is pre-set to 45 minute timer. Press the play button or hit Space to begin.
- 2Customise (optional)
Click the settings icon to change font, colour, background, and size. All settings are encoded in the URL — bookmark it to reuse your exact setup.
- 3Go fullscreen or add to OBS
Press F for fullscreen — ideal for classrooms and presentations. For streaming, enable transparent background and paste the URL into OBS as a browser source.
Frequently Asked Questions
Why is 45 minutes a common class length?
45 minutes is a standard school period length because it balances enough time for meaningful learning while staying within typical student attention spans.
How long is a typical school class period?
Standard middle-school and high-school class periods are 45–55 minutes in most US and UK systems. The 45-minute period is also the standard university lecture length.
What is the 45-minute "ultradian" cycle?
Research on attention and rest cycles suggests the human brain operates on roughly 90-minute ultradian cycles, with a 45-minute peak-focus window in the first half. A 45-minute work block aligns with this peak.