About this 20 hour timer
A free 20-hour countdown timer that starts with one click.
Press start and the timer shows exactly when your 20 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 20 hour timer for
- 20:4 intermittent fasting
- Long fermentation
- Very long cooks
- Event countdowns
20 hours at a glance
| In minutes | 1,200 minutes |
|---|---|
| In seconds | 72,000 seconds |
| Halfway point | 10 hours |
| Share of a day | 83.33% |
| Start now and it ends at | — |
How to use the 20 hour timer
- The timer is ready at 20:00:00. 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
How many minutes are in 20 hours?
20 hours is 1,200 minutes, or 72,000 seconds.
How do I set a 20 hour timer?
Press Start Timer — it is already set to 20:00:00. 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.
Will the timer keep running if I refresh or close the tab?
Yes. The end time is saved in your browser, so reopening this page shows the correct time left. To hear the alarm, keep the tab open and your device's sound on.
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.