20 Minute Timer
A twenty-minute countdown with an alarm — the length of a short power nap, or a repeating reminder to rest your eyes.
20 Minute Timer
20 minutes
Ready
Keys: Space start / pause · R reset · + add a minute · F full screen · Esc stop alarm
How it keeps time
- Length: 20 minutes = 1,200 seconds.
- On Start: end time = the moment you start + 1,200 s, read from your device’s clock.
- Every update: time left = end time − now, rounded up to the whole second — so it never drifts, even in a background tab.
A 20-minute power nap
Mayo Clinic’s advice for healthy adults is to keep naps short: a nap of 20 to 30 minutes is ideal, and the longer you sleep, the more likely you are to wake up groggy. It also suggests napping in the early afternoon, since napping after 3 p.m. can make it harder to sleep at night, and giving yourself a little time to wake up afterward before doing anything that needs a quick response.
If it usually takes you a few minutes to drift off, press +1 min a couple of times before you lie down. Turn your volume up and use Test sound first; the alarm beeps for up to a minute and, on phones that support it, vibrates too. If you need longer, the 30 minute timer covers the top of Mayo Clinic’s range.
The 20-20-20 rule for screen time
To ease digital eye strain, the American Optometric Association recommends the 20-20-20 rule: every 20 minutes, take a 20-second break and look at something 20 feet away. Tick Repeat and this timer becomes that reminder — every 20 minutes it plays a short chime and immediately starts the next 20, timed from the exact end of the last one so the reminders never drift. The AOA also recommends a 15-minute break after two hours of continuous screen use; the 2 hour timer can remind you of that.
How this timer works
Press Start, tap the digits or press Space. The timer saves the end time on your device’s clock and shows end time − now, rounded up to the second, so it stays exact even when your browser slows down background tabs; the remaining time also shows in the tab’s title. The alarm is scheduled on the Web Audio clock for the end time and beeps for up to a minute (phones that support it also vibrate). While the timer runs, the page asks the browser to keep the screen on. Nothing is sent anywhere: the timer runs entirely in your browser.
Other timers
Shorter: 15 Minute Timer. Longer: 30 Minute Timer. For any other length, use the countdown timer; to time how long something takes, use the stopwatch. Counting down to a date instead? See the holiday countdowns.
Frequently asked questions
How long should a power nap be?
Mayo Clinic suggests 20 to 30 minutes for healthy adults, taken in the early afternoon. Longer naps make it more likely you’ll wake up feeling groggy.
What is the 20-20-20 rule?
Advice from the American Optometric Association for digital eye strain: every 20 minutes, look at something 20 feet away for 20 seconds.
Can this timer remind me every 20 minutes?
Yes — tick Repeat. Each time it reaches zero it plays a short chime and starts the next 20 minutes automatically.