Is It Better to Sleep at 10 or 11 PM?

Both 10 PM and 11 PM are healthy bedtimes. The better one for you is whichever gives you about 7.5 hours of sleep before your alarm, every day. With a 5:45 AM alarm, that's a 10 PM bedtime. With a 6:45 AM alarm, it's 11 PM. Both assume about 15 minutes to fall asleep.

If your alarm allows either, there's some evidence that falling asleep in the 10 o'clock hour may have a slight edge, covered below.

Is it better to sleep at 10 or 11?

It depends mostly on when you have to wake up. Here's what each bedtime gives you.

So the quick rule:

• Alarm between about 5:15 and 6:15 AM: 10 PM is the better bedtime. An 11 PM bedtime would leave you under 7 hours.
• Alarm between about 6:15 and 7:15 AM: either works. Pick the one that lands closest to a full cycle.
• Alarm after about 7:15 AM: 11 PM, or even later. A 10 PM bedtime would mean more than 9 hours, and many adults will just lie awake.

For a different alarm time, the sleep calculator gives the matching bedtime in one tap.

Does the clock time itself matter?

A little, possibly. A large UK Biobank study measured when about 103,000 adults actually fell asleep, using wrist-worn trackers, then followed them for about 5.7 years. People who fell asleep between 10:00 and 10:59 PM had the lowest rate of cardiovascular disease.

Compared with that group, the risk was about:

Three things to keep in mind before you change anything:

1. This is about falling asleep, not getting into bed. A 10 PM bedtime usually means asleep around 10:15, inside the lowest-risk hour. An 11 PM bedtime usually lands in the 11 o'clock hour.
2. Earlier isn't automatically better. Falling asleep before 10 was linked to higher risk too.
3. It's an observational study. It shows a link, not proof that the clock time caused the difference. The link was stronger in women, and in men only the before-10 group stood out.

The takeaway is modest: if 10 and 11 fit your life equally well, 10-something may have a small edge. It's not a reason to lose sleep or lie awake for an hour.

Is sleeping before midnight better?

Sleep before midnight doesn't count double. That's a myth. An hour of sleep is an hour of sleep, whether it starts at 10 PM or 1 AM.

There's a grain of truth in it, though. Deep sleep is packed into the first few cycles of the night, whenever the night starts. And for most people with a normal workday, falling asleep before midnight is simply what makes 7 or more hours possible. Someone asleep at 12:30 AM with a 6:30 AM alarm gets 6 hours, not because of midnight, but because of the alarm.

If you're a natural night owl who can sleep until 8 or 9 AM, a later window can be perfectly healthy. Best time to sleep and wake up covers why regular timing matters more than the exact hour.

What matters more than 10 vs 11

In rough order:

1. Getting at least 7 hours. Adults need 7 or more hours a night.
2. Keeping it consistent. In a study of about 60,000 adults, people with the most regular sleep and wake times had a lower risk of dying over the following years than those with the least regular schedules. A 10:30 PM bedtime you keep every night beats a 10 PM bedtime you hit twice a week.
3. Matching your body clock. If you're never sleepy before 11:30, forcing 10 PM mostly means lying awake. See good bedtime for adults for the latest bedtime that still works with your alarm.

How to move from 11 to 10

If you've decided 10 PM suits you better, don't jump the full hour tonight. Move 15 minutes every 3 days, and move your alarm with it.

That takes about two weeks. It helps to get outside soon after waking, dim the lights in the last hour before bed and keep afternoon caffeine early. For a 10 PM bedtime, an 8 oz coffee should be finished by about 12:20 PM to drop below 25 mg. The caffeine calculator checks other drinks.