20 Minute Timer
Twenty minutes, counting down, with a sound at zero.
Runs entirely in your browser
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Laps
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Twenty minutes, counting down. Press Start, or tap the space bar, and leave the tab open.
Twenty minutes is the nap length, and that is not folklore. Sleep cycles run about ninety minutes, and waking from the deep stage in the middle of one is what produces the grogginess that makes people swear off napping. Twenty minutes is short enough to stay in the light stages at the start, which is why the advice keeps landing on that number.
It is also a common length for a bake, a soak, a marinade and a stretch of focused reading, all things you want to be told about rather than watch.
Type any other length into the boxes. The ten minute timer and the twenty-five minute timer are the nearest neighbours.
How to use it
- Press Start, or the space bar, and the countdown begins.
- Leave the tab open. It keeps time whether or not you are looking at it.
- Change the minutes and seconds in the boxes for any other length.
Questions
Is twenty minutes the right length for a nap?
It is the usual advice, because a sleep cycle runs about ninety minutes and twenty keeps you in the lighter stages near the beginning of one. Waking out of the deep stage in the middle is what causes the heavy, worse-than-before feeling people associate with napping.
Will the timer ring if my screen locks?
Not reliably. A locked phone suspends the tab, and while the count is right when you unlock, the sound at zero may not play. For a nap, keep the screen awake or use the device's own alarm, which the operating system is allowed to wake for and a web page is not.
Does the timer keep running if I switch tabs?
Yes. The count comes from the clock rather than from a tick that a background tab would slow down, so it is right when you come back however long you were away. Closing the tab does end it, since nothing is stored anywhere.
Will it make a sound when it finishes?
It rings at zero. Browsers block sound until a page has been interacted with, and pressing Start counts, so a timer you started will always be able to ring. Check the tab is not muted if you hear nothing.
Is anything sent anywhere?
No. The timer is arithmetic on your own clock, running in this tab, and the page makes no request of its own. It works with the network off and keeps no record of what you timed.
Other lengths
The same timer on a different duration. Any of them takes a length of your own once you are there.
Your data stays on your device
Everything above runs inside your browser as WebAssembly compiled from Rust. Nothing you type is uploaded, logged or stored on a server. You can load this page once, go offline, and it still works.
This page makes no requests at all, to anywhere. That is not a promise in the copy: it is a Content-Security-Policy header your browser enforces, and connect-src on it is none. Open the network tab and watch nothing happen.