24 hour timer
A free 24 hour timer set to one full day, 24:00:00, with the end time saved in your browser. Reopen the page tomorrow and it shows exactly how long is left, something a phone's timer app rarely survives. Also searched as 24 hr timer, one day timer, 1440 minute timer.
What a one-day countdown is for
| Use | Time | Note |
|---|---|---|
| 24-hour fast | 24 h from the last meal | Not for everyone; see the FAQ. Not medical advice |
| Once-daily medication | Same time each day | A reminder only; follow your prescriber or pharmacist |
| Marinating meat | 2 to 24 h in the refrigerator | Acidic marinades can turn fish and chicken mushy past a few hours |
| Quick refrigerator pickles | 24 h | Edible after an hour, better after a day |
| Cold-proofed bread dough | 12 to 24 h in the fridge | See the bread proofing timer |
| Grout or wood glue cure | 24 h | Keep the area dry and unloaded until the alarm |
| 24-hour challenge or readathon | 24 h | Press F for a fullscreen display |
Shorter windows
Most eating windows and dosing intervals are shorter than a day. The 12 hour timer covers twice-daily medication and a 12:12 window; the 8 hour timer covers a night's sleep or a shift. For 16:8 fasting, click the digits and type 16 hours.
Making a day-long timer reliable
No device stays awake for a day by default, so plan for it. On a desktop, keep the tab open, turn off display sleep, and tick Notify for a system notification. On a phone, the browser is muted once the screen locks, so the alarm will not sound; the saved end time still lets you check progress whenever you unlock. If the exact moment matters, back it up with the phone's own alarm. The alarm clock page explains how to count down to a specific time of day, and the countdown timer accepts any length up to 99 hours.
Frequently asked questions
What is the longest timer I can set?
Ninety-nine hours. Click the digits and type the hours, minutes and seconds; the 24 hour preset is just a starting point.
Is a 24 hour fast safe?
It is not for everyone, including people who are pregnant, diabetic, underweight or on certain medications. Talk to a clinician before trying it. This page is a timer, not medical advice.
Will I hear the alarm a day later?
Only if the device is awake with the tab open at that moment. Reloading shows the correct remaining time, but a sleeping device cannot play sound.
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