12 Hour Timer
A free online 12 hour timer that counts down 12 hours (720 minutes) and sounds an alarm when it's done. Press Start or hit the Space bar.
Keyboard: Space start/pause · R reset · F full screen
How to use the 12 hour timer
- Press Start (or the Space bar). The ring shows how much time is left.
- Pick an alarm sound. Use Test sound to check your volume first.
- Pause, reset or add time whenever you need. Full screen makes the numbers easy to see from across a room.
- When the timer hits zero, the alarm rings for up to 30 seconds. Press Stop alarm to silence it.
Ways to use a 12 hour timer
- Long study or work blocks
- Cooking, baking and slow roasting
- Screen-time and gaming limits
12 hours in other units
- Seconds
- 43,200
- Minutes
- 720
- Hours
- 12
- Clock format
- 12:00:00
Frequently asked questions
How do I set a timer for 12 hours?
Press Start above. The 12 hour timer is already set to 12:00:00, so it begins counting down right away, and an alarm sounds when it reaches zero.
Will the alarm ring if I switch tabs or lock my screen?
The alarm is scheduled with your browser’s audio engine the moment you press Start, so it rings on time even in a background tab. Keep the tab open and your volume up. Some phones pause web pages when the screen locks, so leave the screen on for short timers (the timer asks your phone to keep the screen awake while it runs).
How many seconds are in 12 hours?
12 hours is 43,200 seconds.
Can I pause or add more time?
Yes. Press Pause (or the Space bar) to pause, and use the +1 min button to add time while the timer runs.
Is this timer free?
Yes. It runs in your browser with no app, account or sign-up, and works on phones, tablets and computers.