12 hour timer

A free 12 hour timer that opens at 12:00:00. Press Space and the end time is saved, so even if you close the laptop and reopen it hours later the countdown shows the right time left. Also searched as 12 hr timer, twelve hour timer, half day timer.

Twelve-hour intervals people track

Use	How to set it
12:12 eating window	Start at your last bite; the alarm marks the earliest next meal. A longer fast uses the 24 hour timer
Medication every 12 hours	Start when you take a dose; tick Notify. Not medical advice; follow your prescriber or pharmacist
Cold brew coffee	12 to 18 hours in the fridge; see the coffee timer
Soaking dried beans	8 to 12 hours, then drain and rinse
Sourdough cold proof	12 to 24 hours in the fridge, shaped and covered
12-hour shift (7 to 7)	Start at clock-in; pair with a 4 hour timer on Repeat for break checks

Timers versus clock times

A twelve-hour countdown started at 8:00 pm ends at 8:00 am, which is simple to reason about. For any other target, the alarm clock page shows how to turn a time of day into a countdown. If you only need the morning half, the 8 hour timer covers a night's sleep.

Keeping a 12-hour timer alive

Twelve hours is longer than any device stays awake on its own. Keep the tab open and disable display sleep, or accept that you will see the remaining time on return but miss the sound. On desktop, tick Notify so a system notification fires if the browser is open. Phones mute browser audio when locked. If the alarm must wake you, use the phone's own alarm and keep this page for the countdown.

Other lengths

Type any time up to 99 hours into the countdown timer. Eating windows other than 12:12, such as 16:8, are set the same way: click the digits and enter 16 hours. This page is a timer, not medical advice.

Frequently asked questions

Can I use the 12 hour timer for medication every 12 hours?

As a reminder, yes. Start it when you take a dose and tick Notify. It is not medical advice; follow your prescriber or pharmacist on timing and missed doses.

How long should cold brew steep?

Twelve to eighteen hours in the refrigerator for most ratios. Twelve gives a lighter cup; longer brings out more body and bitterness.

Will the timer still be right after my laptop sleeps overnight?

Yes, the remaining time is recalculated from the saved end time when the page wakes. The alarm itself only plays if the device is awake at zero.