About this 12 hour timer
Half-day countdown perfect for medication dosage intervals (every 12 hours) and overnight rest timing.
Press start and the timer shows exactly when your 12 hours will be up. It rings at zero, goes full screen for classrooms and kitchens, and remembers where it was if you refresh the page.
What people use a 12 hour timer for
- 12-hour medication intervals (always follow your prescriber)
- 12:12 intermittent fasting
- Overnight sourdough and cold dough proofing
- 12-hour work shifts
12 hours at a glance
| In minutes | 720 minutes |
|---|---|
| In seconds | 43,200 seconds |
| Halfway point | 6 hours |
| Share of a day | 50% |
| Start now and it ends at | — |
How to use the 12 hour timer
- The timer is ready at 12:00:00. Tap Edit time to change it.
- Press Start Timer (or the space bar). The finish time appears under the digits.
- Press Full screen to fill the screen — handy for classrooms, meetings and kitchens.
- When it reaches zero an alarm plays until you press Stop Alarm.
Keyboard shortcuts
- Space start / pause
- R reset
- F full screen
- M mute
Frequently asked questions
Will a 12 hour timer keep running if I close the page?
The countdown is saved in your browser. Reopen this page and it picks up exactly where it should be. Keep the tab open (and your device awake) if you need to hear the alarm.
How many minutes are in 12 hours?
12 hours is 720 minutes, or 43,200 seconds.
Can I use it for medication every 12 hours?
Yes, as a reminder. Start it right after a dose and the screen shows when the next one is due. Always follow the schedule your doctor or pharmacist gives you.
How do I set a 12 hour timer?
Press Start Timer — it is already set to 12:00:00. To change the length, tap Edit time, enter hours, minutes and seconds, then press Set. You can also add a minute at any point with +1 min.
Does the timer work on a phone?
Yes. It runs in any modern mobile browser with no app or sign-up, and it asks your phone to keep the screen awake while it runs.