30 Minute Timer

Everything is set for half an hour when the page opens: 30 in the Minutes box, 1,800 seconds in all.

1. Look at the three fields. Hours and Seconds hold 0 and Minutes holds 30. If a recipe asks for 28 minutes, type 28 and the display follows.
2. Use Label (optional) for a short name, such as Cookies or Chapter 4, so the finish message says what ended.
3. Keep Play a sound when time is up on if you will be in another room, and turn it off for quiet work.
4. Press Start. For the next half hour, the tab title carries the time left, for example 12:45 left.
5. Press Pause if you need a moment and Resume to carry on, or Reset to return to 30:00. Full screen gives a clock that is readable from a distance.

You can also press Space to start or pause, and R to reset when the timer is stopped.

If you change your mind about the length, edit the boxes while the timer is stopped or paused. The clock goes back to the new total, and you simply press Start again. Changes made while it is running only touch the display until you press Reset.

Thirty minutes divides neatly, which is part of why it is so common. Two of them make an hour, and the half hour fits a surprising range of plans:

It also fits in a day with other commitments. Say you plan 30 minutes of cooking, 45 minutes of homework and another 30 minutes of reading. The time calculator adds them up to 105 minutes, which is 1 hour 45 minutes, so starting at 6:00 pm you would finish at 7:45 pm with no breaks in between.

Billing is a different use. A half-hour consultation at $60 an hour costs $30, because 30 minutes is 0.5 hour. If you need the same conversion for other amounts, the time converter turns minutes into decimal hours and seconds.

A half hour also suits a full study session when you add a break afterward. The Pomodoro timer does that automatically if you set the focus session to 25 minutes and the short break to 5.

For food, the timer is a reminder to check, and not proof that something is ready. Ovens differ, trays and tins differ, and a small batch of cookies may be done sooner than the recipe says. Start the timer once the food is actually in the oven, and look at it before the end, particularly with a new recipe. For slow cookers, a half-hour check is a reasonable use, but follow the recipe and the appliance instructions for the real cooking time and food safety.

When the count reaches zero the display switches to a done state and the message says Time is up, followed by your label. To run another half hour, press Start or Space again.

• The page must stay open. If you close the tab, the countdown ends. On a phone, a locked screen may pause the page and the alarm.
• The alarm is brief. It is four tones lasting a little over a second, so keep the volume up and stay within earshot when it matters.
• No saved timers. Nothing is stored between visits, and there is no second timer for a second dish.

For half-length checks, the 15 minute timer splits the half hour in two. For longer jobs, the 60 minute timer covers a full hour.

A half hour is also a friendly length for building a new habit. Reading, language practice or a walk fit comfortably, and finishing one block gives a clear stopping point. If it turns out to be too long on a busy day, drop to a shorter block instead of skipping the habit completely.