30 Minute Timer
A half-hour countdown with an alarm and huge digits that stays accurate even when the tab is in the background.
30 Minute Timer
30 minutes
Ready
Keys: Space start / pause · R reset · + add a minute · F full screen · Esc stop alarm
How it keeps time
- Length: 30 minutes = 1,800 seconds.
- On Start: end time = the moment you start + 1,800 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.
Thirty minutes, five days a week
The Physical Activity Guidelines for Americans recommend at least 150 minutes of moderate-intensity aerobic activity a week for adults. A common way to reach it is 30 minutes on five days: 30 × 5 = 150. The guidelines count activity of any length, so a 30-minute session can also be split into shorter pieces — the 10 minute timer works for that.
The 30 minutes before a blood-pressure reading
The American Heart Association advises not smoking, not drinking caffeinated drinks and not exercising in the 30 minutes before you measure your blood pressure, because all three temporarily raise it. Start this timer after your coffee, then rest quietly for the last five minutes before you take the reading.
Other half-hour jobs
- Study blocks. Thirty minutes of focused work followed by a short break is a slightly longer version of the Pomodoro cycle.
- Naps. Mayo Clinic suggests keeping naps to 20–30 minutes and not regularly sleeping longer than 30, to avoid waking up groggy.
- Cooking and baking, where the remaining time in the browser tab lets you follow a recipe in another tab.
Pausing is safe: the timer remembers exactly how much time was left, and when you resume it sets a new end time from that.
This page is general information, not medical advice. Follow the instructions of your own doctor or care team.
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: 20 Minute Timer. Longer: 45 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
Is 30 minutes of exercise a day enough?
Thirty minutes of moderate activity on five days a week adds up to the 150 minutes a week the Physical Activity Guidelines for Americans recommend for adults, along with muscle-strengthening activity on two days a week.
Why wait 30 minutes before checking blood pressure?
The American Heart Association says smoking, caffeine and exercise all raise blood pressure temporarily, so it advises avoiding them for 30 minutes before a reading.