The 10-3-2-1-0 formula comes from Craig Ballantyne, a fitness coach and writer, who set it out on his Early To Rise blog in January 2016 as the 10-3-2-1-0 Formula to Get More Done. Some health sites trace it to a physician's Instagram post from 2021, which is when it spread; Ballantyne's version is five years older. This page is our own worksheet built on his countdown; neither Ballantyne nor Early To Rise had a hand in it or endorsed it.

The countdown

Choose the time you want to be asleep, then count backward:

• 10 hours before bed: no more caffeine.
• 3 hours before: no more food or alcohol.
• 2 hours before: no more work.
• 1 hour before: no more screens.
• 0: the number of times you hit snooze in the morning.

The shorter 3 2 1 sleep rule is the middle of the same countdown: the dinner, work and screen cut-offs without the caffeine and snooze bookends.

The arithmetic is easy for a 10:30 pm bedtime and fiddly for a late one. If lights out is 12:30 am, caffeine stops at 2:30 pm, food and alcohol at 9:30 pm, work at 10:30 pm and screens at 11:30 pm. The page does that counting for you.

How this page works

Pick lights out from the common times, or nudge it a quarter hour at a time anywhere from 7:00 pm to 3:00 am. A painted candle then marks itself like an old candle clock. The top band is your last caffeine, faint bands below it count off the hours in between, and three marks crowd together near the holder: dinner, work and screens. The bunching is the lesson: three of the five cut-offs fall in the last three hours of your evening.

Each morning, log the night that just ended. All five numbers start out held; tap the ones that slipped and log the night. Log the same night again and the page corrects that entry rather than adding a second one. The record holds fourteen nights.

Once three nights are in, the page reads the record. If one cut-off has slipped more than the others, and at least twice, it names that one, turns its mark ember on the candle and asks for a single fix, from suggestions to tap or a line of your own. Five rules at once are hard to keep. One is something you can work on.

What the evidence says, piece by piece

The rule is a popular rule of thumb, not a tested protocol, and nobody has trialed the five parts together. Some numbers have research behind them; others are round figures.

Caffeine, ten hours. In a 2013 study, 400 mg of caffeine taken six hours before bed still disrupted sleep, measured at home with a portable sleep monitor, and the authors advised stopping substantial caffeine at least six hours before bed. Ten hours adds a cushion to that. How much you need depends on your cups and how fast you clear caffeine, which the Caffeine Calculator works out for your day.

Food and alcohol, three hours. The clearest support concerns heartburn, which was Ballantyne's own reason. In a case-control study, people who went to bed less than three hours after dinner had more than seven times the odds of reflux disease of people who waited four hours or more. That is an association, not proof, and it says nothing about alcohol, so treat three hours as the least you give a drink, not a sign it has worn off.

Work, two hours. We found no study that tests a two-hour work cut-off. The idea is to give a busy head time to settle, and Ballantyne's own fix was a five-minute brain dump on paper, which the Bedtime Brain Dump turns into a short worksheet.

Screens, one hour. The closest test is a small randomized trial in which people kept their phones away for the last thirty minutes before bed for four weeks. They fell asleep faster and slept longer than a control group. That backs the direction of the rule with half its window.

Zero snooze presses. This is the part the research supports least. In a lab study of habitual snoozers, thirty minutes of snoozing cost about six minutes of sleep and left their thinking just after waking no worse, sometimes better, with no clear effect on mood or sleepiness. Keep the zero if a clean start suits you; it is a preference, not a finding.

When to use it

Use it for two weeks when you are resetting your nights, after travel, a new job or a run of short sleep. Use it when you suspect one habit is costing you sleep but cannot tell which. If you work nights, this rule was not built for your schedule, which is why the candle stops at 3:00 am.

When to talk to a doctor

These cut-offs tend the conditions around sleep. If you hold them for a few weeks and still lie awake most nights, or wake unrefreshed however long you sleep, talk to a doctor. Insomnia that lasts has a treatment of its own, cognitive behavioral therapy for insomnia (CBT-I), which physicians' guidelines recommend first, and two weeks of a Sleep Log gives that conversation something to start from.