Sleep Schedule Calculator
Work out what time to go to bed so you get the sleep you need before your alarm, based on age-group recommendations and how much of your time in bed you actually sleep.
Last updated: October 2026
Recommended Bedtime
10:05 PM
This calculator gives an estimate for general information only. It is not medical advice and does not replace a doctor, pharmacist or other qualified health professional. Always check with them before acting on the result, especially for medication doses, children, pregnancy or a medical condition, and follow the guidelines of your local health authority.
Formula below · 3 sources (pubmed.ncbi.nlm.nih.gov, CDC, sleepfoundation.org) · Updated Oct 2026
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About this calculator
The calculator works backward from your alarm.
1. Sleep target. Sleep experts recommend 7 to 9 hours a night for adults 18 to 64 and 7 to 8 hours for adults 65 and older, and at least 7 hours for every adult. The goal you choose sets the target within that range: Young adult 7 / 8.5 / 9 hours, Adult 7 / 8 / 8.5 hours, Older adult 7 / 7.5 / 8 hours for minimum / typical / extra. 2. Time in bed. Nobody sleeps for every minute in bed: it takes a while to fall asleep and most people wake briefly during the night. Sleep efficiency is the share of time in bed spent asleep; about 85% or more is considered normal. Time in bed = sleep target ÷ efficiency. 3. Bedtime = wake time − time in bed, rounded to the nearest 5 minutes.
With the defaults (adult, typical need, typical sleeper, 7:00 AM alarm): 8 ÷ 0.90 = 8.89 hours, or 8 h 53 min, in bed. Bedtime is 10:07 PM, shown as 10:05 PM.
Sleep runs in cycles of roughly 90 minutes, but cycle length varies from person to person and through the night, so planning total sleep is more reliable than counting exact cycles. A regular schedule, including on weekends, matters as much as the bedtime itself.
This tool is for healthy adults. Teenagers and children need more sleep, and shift work or a sleep disorder calls for advice from a clinician, not just an earlier bedtime. If you regularly sleep the recommended amount and still feel unrested, or you snore loudly or stop breathing in your sleep, talk to a doctor. This is general information, not medical advice.
| Age | Recommended | May be appropriate |
|---|---|---|
| School age (6–13) | 9–11 hours | 7–12 hours |
| Teenagers (14–17) | 8–10 hours | 7–11 hours |
| Young adults (18–25) | 7–9 hours | 6–11 hours |
| Adults (26–64) | 7–9 hours | 6–10 hours |
| Older adults (65+) | 7–8 hours | 5–9 hours |
How to use
Choose your age group, the time you need to be up, your sleep goal and how well you usually sleep. The result is the time to turn the lights out. Example 1 (defaults): adult, 7:00 AM, typical need (8 h), typical sleeper (90%). 8 ÷ 0.90 = 8 h 53 min in bed, so bedtime is 10:05 PM. Example 2: adult, 6:00 AM, at least 7 hours, sound sleeper (95%). 7 ÷ 0.95 = 7 h 22 min in bed, so bedtime is 10:40 PM. Example 3: older adult, 6:30 AM, typical need (7.5 h), restless sleeper (85%). 7.5 ÷ 0.85 = 8 h 49 min in bed, so bedtime is 9:40 PM.
Frequently asked questions
How much sleep do adults need?
At least 7 hours a night. The National Sleep Foundation recommends 7 to 9 hours for adults 18 to 64 and 7 to 8 hours for those 65 and older; the American Academy of Sleep Medicine also recommends 7 or more hours for adults. Regularly sleeping less than that is linked to poorer health and more accidents.
Why does the calculator add time beyond my sleep goal?
Because you are not asleep the whole time you are in bed. If you need 8 hours of sleep and sleep 90% of the time in bed, you need about 8 h 53 min in bed. Choosing 'Restless' adds more time; if you are often awake in bed for long stretches, that is worth raising with a doctor.
Should I time my alarm to 90-minute sleep cycles?
Cycles average about 90 minutes but vary between people and lengthen through the night, so an exact cycle count is guesswork. Getting enough total sleep on a consistent schedule does more for how you feel in the morning.
Can I catch up on sleep at the weekend?
A longer sleep helps after a short night, but sleeping in by hours shifts your body clock and makes Monday harder. A steady wake time every day, with an earlier bedtime when you are behind, works better.
Is this right for teenagers?
No. Teens 14 to 17 need 8 to 10 hours and younger children more, and teenagers' body clocks naturally run later. Use age-specific guidance for them.
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