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20 Second Timer
Your 0:20 countdown is ready: press Start (or Space) and an alarm sounds after twenty seconds, with 3-2-1 beeps at the end. Perfect for hand washing, Tabata work intervals and the 20-20-20 eye break.
0:20
Ready
Presets
Shortcuts: Space start / pause · R reset · F fullscreen. Add ?s=40 to the address to open a custom number of seconds.
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How to use the 20 Second Timer
- Press Start or hit the Space bar. The 0:20 countdown begins immediately.
- Leave the 3-2-1 beeps on to hear when the last seconds are ticking away.
- Fine-tune the length with the ± buttons or pick another preset.
- Choose an alarm sound and volume, then press Play test sound to check you can hear it.
- When time is up, press Stop alarm or Space. Press R to reset to 0:20.
How long is 20 second?
| Measure | 20 Second equals |
|---|---|
| Seconds | 20 s |
| Milliseconds | 20,000 ms |
| Hours | 0.005556 h |
| Share of a day | 0.0231% (1/4320 of a day) |
| Walking at 5 km/h (3.1 mph) | about 0.028 km (0.017 mi) |
| Speaking at 130 words per minute | about 43 words |
| Reading at 230 words per minute | about 77 words |
What you can do in 20 second
| Activity | Why 20 second works |
|---|---|
| Hand washing | Health agencies recommend scrubbing hands with soap for at least 20 seconds |
| Tabata | The classic Tabata protocol is 20 seconds of work and 10 seconds of rest, 8 times |
| 20-20-20 eye break | Look at something 20 feet away for 20 seconds after 20 minutes of screen time |
| Sprint drill | A short all-out effort between longer rests |
| Brainstorm burst | Write down as many ideas as possible before the alarm |
| Microwave reheating | Short bursts when warming small portions |
How the countdown keeps exact time
When you press Start, the timer records the end moment as start time + 20,000 ms on the browser's monotonic clock (performance.now()). Every screen update subtracts the current time from that end moment instead of counting ticks, so a throttled background tab or a busy computer cannot make it fall behind. Pausing stores the time left, and Resume sets a new end moment that far in the future.
Frequently asked questions
How long should I wash my hands?
Scrub with soap for at least 20 seconds, covering the backs of your hands, between fingers and under nails, then rinse. Start this timer when you begin scrubbing.
How many milliseconds are in 20 seconds?
20 seconds is 20,000 milliseconds, or one third of a minute.
Can I use this for Tabata?
Yes for single rounds: 20 seconds work, then reset for the 10 second rest. For automatic rounds use the interval timer, which alternates work and rest for you.
Will I hear a warning before the end?
Yes. With "Beep at 3, 2, 1 seconds left" switched on, you hear three short ticks before the alarm.
Can I change the length?
Use the ±5 s buttons, a preset from 10 seconds to 1 minute, or ?s= in the address, for example ?s=25.
Does it work on a phone?
Yes, in any modern mobile browser. Keep the screen on, because some phones pause web pages when they lock.
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