Set 12 Hours Timer Online
Set timer for 12 Hours directly in your browser. This free online countdown clock counts down from 12 hours to zero and plays a loud alarm when time is up. To start the timer, simply click the Start button above.
Popular Uses
- Half-Day Countdown - mark the exact halfway point of any 24-hour event, race, or endurance challenge.
- Overnight Refrigerator Proof - cold-proof enriched doughs like brioche or cinnamon rolls in the fridge overnight for 12 hours.
- 12:12 Intermittent Fasting - complete the beginner 12-hour fast from dinner to breakfast for gentle circadian metabolic benefits.
- Shift Worker Tracker - time a standard 12-hour hospital, factory, or emergency-services shift from start to finish.
- Long-Haul Flight - track a 12-hour transatlantic or transpacific flight duration from gate departure to landing.
Frequently Asked Questions
Does this 12 hours timer make a sound?
Yes. When the countdown reaches zero, the browser plays a short alarm chime. Keep the tab open and your device volume enabled.
Can I use this timer in full screen?
Yes. Use the full-screen button to turn the countdown into a large display for classrooms, workouts, meetings, cooking, or livestreams.
How many seconds is this timer?
This countdown is exactly 43,200 seconds long.
More Timer Durations
Need a different time? Select from our quick preset timers below.
Seconds:
Minutes: