School Night Bedtime Calculator
Enter age, school start time and morning routine time to find a bedtime window that protects enough sleep.
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Find the right school night bedtime. Enter age, school start time and travel time to get a wake up time and bedtime window based on CDC sleep guidance.
School night bedtime calculator
Enter your child age, school start time and how long getting ready and travel take. The calculator works out a wake up time and a bedtime window.
How the school bedtime is calculated
First the tool subtracts getting ready and travel time from the school start to find the wake up time. Then it subtracts the recommended hours for the age: 9 to 12 hours for ages 6 to 12 and 8 to 10 hours for ages 13 to 18, following the CDC and American Academy of Sleep Medicine. Finally it allows about 15 minutes to fall asleep.
Making the bedtime stick
- Start the wind down 45 to 60 minutes before lights out: bath, book, dim lights.
- Put screens away at least 30 to 60 minutes before bed.
- Keep weekend bedtimes within an hour of school nights.
- Use morning light and breakfast to anchor the wake up time.
- For teenagers, expect the body clock to run later and use a steady wake time to help it.
See also sleep for school children, sleep for teenagers and the sleep needed by age calculator.
Frequently asked questions
What time should a child go to bed on school nights?
Count back from the wake up time. A child who wakes at 7:00 AM and needs 10 hours should be asleep by 9:00 PM, so lights out around 8:45 PM.
How much sleep do school age children need?
The CDC and AASM recommend 9 to 12 hours for ages 6 to 12 and 8 to 10 hours for ages 13 to 18.
What if my child cannot fall asleep at the new bedtime?
Move bedtime earlier by 15 minutes every few nights, keep a fixed wake up time, use morning light and keep the evening calm and dim.
Why am I still tired after 8 or 9 hours of sleep?
Common reasons include irregular sleep times, alcohol or late caffeine, a warm or noisy room, waking at the wrong point in a cycle, or sleep that is fragmented. Loud snoring with breathing pauses, or sleepiness that affects driving or work, should be checked by a doctor.
How do I adjust to daylight saving time?
Move your schedule by 15 to 20 minutes over several days before the change and get morning light afterwards. Expect a few days of adjustment.
How many sleep cycles do I need per night?
Most adults do well with 5 cycles (about 7.5 hours) and some need 6 (about 9 hours). Four cycles, about 6 hours, is short for most people and is better used as an occasional fallback than a habit.
Is 6 hours of sleep enough?
For most adults it is below the recommended 7 hours. Some people feel fine for a while, but research on chronic sleep restriction found that performance slips even when people do not feel very sleepy. Treat 6 hours as a short night and plan recovery sleep.
How do I move my bedtime earlier?
Shift it by 15 to 30 minutes every two or three days while keeping the wake time fixed, get bright light after waking and dim lights for an hour before bed.