20 minutes timer

What a 20-minute timer is good for

Twenty minutes is a versatile, sustainable block. It is the upper bound of a refreshing power nap, the recommended cadence for resting your eyes from a screen, a complete short workout, and a focused study or work sprint for people who find the standard 25-minute Pomodoro slightly too long. It is also the interval many soups, sauces and grains need to simmer or cook through.

• •The 20-20-20 eye-rest rule for screen work
• •A short but complete home workout or yoga flow
• •A focused study block, often paired with a 5-minute break
• •Simmering, roasting, or baking steps in cooking
• •The longer end of a restorative power nap

The 20-20-20 rule for screen fatigue

If you work at a screen, the most useful thing a twenty-minute timer can do for you is enforce the 20-20-20 rule, an eye-care guideline endorsed by optometrists worldwide: every twenty minutes, look at something twenty feet (about six metres) away for twenty seconds. The point is that staring at a fixed near distance for long stretches keeps the focusing muscle inside your eye continuously contracted, which contributes to the dryness, blurring and ache of digital eye strain. Looking into the distance relaxes that muscle and gives it a genuine break, and twenty seconds is long enough for it to fully release. Setting a recurring twenty-minute timer is the simplest way to build the habit, because the strain creeps up so gradually that you never notice you are due for a break until your eyes already hurt.

How this 20-minute timer stays accurate

Most browser timers drift, because they count by accumulating small ticks, and browsers deliberately slow those ticks down in background tabs to save battery. This one is different: the moment you press start it records the exact wall-clock time the countdown should end, and every frame it simply measures how long is left until that fixed end time. If you switch tabs, lock your phone, or the tab is throttled, the remaining time is recomputed from the real clock the instant you come back, so a 20-minute timer is still a 20 minutes timer rather than however long the throttled ticks happened to add up to. On phones the page asks for a screen wake lock while the countdown is running, where the browser allows it, so the display does not sleep mid-count. The alarm is synthesised in the browser with the Web Audio API, which means there is no audio file to download and the chime is ready the moment you start.

Other timer lengths

Need a different length? These are the timers people most often reach for alongside a 20-minute timer:

• 15 minutes timer
• 25 minutes timer
• 30 minutes timer

Frequently asked questions

What is the 20-20-20 rule?

Every 20 minutes of screen time, look at something about 20 feet away for 20 seconds. It relaxes the eye's focusing muscle and reduces digital eye strain. A recurring 20-minute timer is the easiest way to remember to do it.

Is 20 minutes too long for a power nap?

It is at the upper edge. Naps of 10 to 20 minutes keep you in light sleep and avoid grogginess; much beyond 20 minutes you risk waking from deep sleep feeling worse. Twenty minutes is a reasonable maximum for a quick recharge.

Can I use the 20-minute timer for studying?

Yes. A 20-minute focus block followed by a short break suits people who find the classic 25-minute Pomodoro slightly long. Pair this with the 5-minute timer for the break interval.

Does the 20-minute timer work offline?

Yes. Once the page has loaded, the countdown runs entirely in your browser using your device clock, so it keeps working with no connection. The alarm is generated in the browser too, so there is no sound file to download.