Good uses for a 20 second timer
- Hand washing: the CDC advises scrubbing with soap for at least 20 seconds
- A plank, wall sit or other short hold
- A 20-second work burst in a Tabata-style round
- Quick turns in board games or charades
- Letting a pan or tool cool for a moment
- Short speaking turns in class
Tips
- Put the timer in Full screen near a sink or on a classroom board so everyone sees the blocks.
- For Tabata (20 seconds work, 10 seconds rest, 8 rounds) with a beep at every change, use the Tabata timer.
- Press Esc or Stop alarm to silence it quickly.
20 seconds in other units
| Unit | 20 seconds |
|---|---|
| Minutes | 0.33 |
| Seconds | 20 |
| Hours | 0.006 |
| Milliseconds | 20,000 |
Questions and answers
How long should I wash my hands?
The US Centers for Disease Control and Prevention says: "Scrub your hands for at least 20 seconds" (CDC, About Handwashing, read 9 November 2026). That is what this timer counts.
Can I see the time without numbers?
Yes. Open View and choose Hide under Numbers. Only the blocks show, which works well for young children.
Does the timer keep running if I switch tabs?
Yes. TimerNook works out the time left from your device clock and a fixed end time, not by counting ticks, so a background tab is still right. While a timer runs, the page also plays a tone too quiet to hear, so the browser keeps the tab awake; your browser may show a speaker icon on the tab. If you also tick "Notify me", you get a system notification at the end.
Will the alarm ring if my phone screen locks?
Not always. Phone browsers can pause web pages when the screen locks, and an iPhone on silent can mute browser sound. Keep the screen on; while the timer runs TimerNook asks the browser to keep the screen awake where that is supported. If the page was paused, the alarm rings as soon as you return.