Best time to go to bed if you wake up at 6, 6:30 or 7 AM

Three alarm times cover a large share of weekday mornings: 6:00, 6:30 and 7:00 AM. Below are the bedtimes for each, worked out in whole sleep cycles.

The assumptions

• A cycle lasts about 90 minutes. The Sleep Foundation describes cycles that average about 90 minutes, with four to six in a typical night.
• You need about 15 minutes to fall asleep. The Sleep Foundation calls 10 to 20 minutes normal for adults. We use the middle.
• Bedtime means getting into bed. So: bedtime = alarm − 15 minutes − cycles × 90 minutes.

Every time below comes from the same function that runs the sleep calculator, and each one is covered by an automated test.

The quick answer

Alarm	6 cycles (9 h asleep)	5 cycles (7 h 30 min)	4 cycles (6 h)
6:00 AM (06:00)	8:45 PM (20:45)	10:15 PM (22:15)	11:45 PM (23:45)
6:30 AM (06:30)	9:15 PM (21:15)	10:45 PM (22:45)	12:15 AM (00:15)
7:00 AM (07:00)	9:45 PM (21:45)	11:15 PM (23:15)	12:45 AM (00:45)

For most adults, the five-cycle column is the practical pick. It gives 7 hours 30 minutes of sleep. CDC's table recommends 7 or more hours for adults 18 to 60. Four cycles is only 6 hours, below that range. Six cycles, 9 hours, is also inside "7 or more," and fits people who know they need more.

For adults 61 to 64, CDC lists 7–9 hours, and both five and six cycles fit. For 65 and older it lists 7–8 hours, which five cycles meets. Teens 13 to 17 are listed at 8–10 hours, so six cycles is the one that lands in their range.

6:00 AM alarm

In bed at 10:15 PM, asleep around 10:30 PM, and five cycles end right at 6:00 AM:

Step by step: 6:00 AM minus 15 minutes is 5:45 AM. Minus 7 hours 30 minutes is 10:15 PM.

6:30 AM alarm

In bed at 10:45 PM. The cycle boundaries fall at 12:30, 2:00, 3:30 and 5:00 AM, and the fifth ends at the alarm:

7:00 AM alarm

In bed at 11:15 PM, asleep by about 11:30 PM:

What if you miss the bedtime?

Say the alarm is 6:30 AM and you get into bed at 11:00 PM instead of 10:45. With 15 minutes to fall asleep, you get four full cycles plus 1 hour 15 minutes of a fifth. The alarm lands 15 minutes before that cycle would end:

Is that a problem? Probably less than it looks. Cycles vary in length, from person to person and from night to night, as the Sleep Foundation notes. The first one often runs 70 to 100 minutes and later ones 90 to 120. A 15-minute miss is inside that wobble. Don't push your bedtime back an hour and a half to "hit a boundary." That would cost you a full cycle of sleep.

The better rule: aim for the five-cycle time, and if you're late, go to bed anyway.

Three habits that make the numbers work

These come from the habits CDC lists for better sleep:

1. Same times every day. CDC's first habit is going to bed and getting up at the same time every day, weekends included.
2. Screens off 30 minutes before bed. CDC suggests turning off electronic devices at least 30 minutes before bedtime. For a 10:45 PM bedtime, that means 10:15 PM.
3. No caffeine late in the day. CDC lists avoiding caffeine in the afternoon or evening. Our caffeine timing guide puts clock times on that advice.

Your own alarm

Different alarm? Slower to fall asleep? Know your cycles run long? The sleep calculator does the same math for any time, lets you change the 15 and the 90, and also works in reverse: "if I go to bed now, when should I wake up?" The 90-minute cycle guide explains how far the answer can move.

If you keep a steady schedule and still wake up exhausted, the numbers are not the issue. NINDS advises seeing a doctor if you have problems sleeping or if you feel unusually tired during the day.