Make room for enough sleep
Most adults need 7–9 hours. Plan for the rest you need, then add a little time to drift off.
Read about sleep durationFREE SLEEP CALCULATOR
Sleep calculator.
Sweeter mornings.
Find your bedtime or wake-up time with our free sleep calculator. Plan a nap, too, for a more rested day.
Give tomorrow a softer start.
Free to use. Easy to make a habit.
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Your bedtime options
These are estimates, not predictions of your sleep stages. Most adults need 7–9 hours; enough total sleep matters more than exact cycle timing.
A LITTLE SLEEP SCIENCE
A better night, one small step at a time.
Your body isn’t a stopwatch. Think of this as a useful starting point.
Work with your rhythm
Sleep moves through repeating stages. We use 90 minutes as an estimate, but real cycles vary.
Understand sleep cyclesKeep a steady routine
A consistent bedtime and wake-up time can help your body settle into a rhythm. Start with a routine you can keep.
Explore healthy sleep habitsBEFORE YOU DOZE OFF
A few things
you might wonder.
Simple answers for a calmer night.
How much sleep do I need?
Most adults need 7–9 hours of sleep each night. Start with that range, then allow extra time to fall asleep. Snoozely shows the estimated time asleep for each option; a shorter option is for comparison, not a recommendation to cut your sleep.
NHLBI: recommended sleep duration
What time should I go to bed?
Work backward from when you need to wake up, allowing enough sleep plus time to fall asleep. For a 7:00 AM wake-up, the default settings give 9:45 PM for 9 hours of sleep or 11:15 PM for 7 hours 30 minutes. Both include 15 minutes to fall asleep. Choose “Wake up at” to calculate your own bedtime.
What time should I wake up if I go to sleep now?
Choose “Sleep now” and calculate from your current local time. Snoozely adds your fall-asleep allowance and shows several estimated wake-up times, with dates when the calculation crosses midnight. Choose an option that gives you enough sleep, then set a separate alarm.
How many hours of sleep will I get?
Subtract the time you expect to spend falling asleep from the time between getting into bed and waking up. For example, 11:00 PM to 7:00 AM is 8 hours in bed, or an estimated 7 hours 45 minutes asleep with a 15-minute allowance. Snoozely’s result cards show estimated time asleep, not total time in bed.
How do I calculate how much sleep I got last night?
Count the time from when you fell asleep to when you woke up, then subtract any time you were awake during the night. If you only know when you got into bed, also subtract your estimated time to fall asleep. Snoozely plans future sleep times; it does not track or measure how much you actually slept.
How does the sleep calculator work?
Snoozely counts backward from a wake-up time, or forward from a bedtime, using your estimated sleep-cycle length and time to fall asleep. The defaults are a 90-minute cycle and 15 minutes to fall asleep. Open “Personalize your sleep” to change these assumptions. The results are planning estimates, not measurements of your sleep.
Does the amount of sleep I need change with age?
Yes. Sleep needs differ by age. NHLBI recommends 9–12 hours for children ages 6–12, 8–10 hours for teenagers ages 13–18, and 7–9 hours for adults. Snoozely’s calculator is intended for adults and does not provide an age-based sleep prescription for children.
NHLBI: sleep needs by age
Can a REM sleep calculator tell me when to wake up?
A clock-based calculator cannot identify your REM sleep or predict exactly which sleep stage you will be in when an alarm rings. Snoozely estimates timings from your chosen settings. Use enough total sleep and a consistent routine as your starting points rather than relying on a predicted REM boundary.
NHLBI: sleep phases and stages
Is every sleep cycle exactly 90 minutes?
No. NHLBI describes sleep cycles as roughly 80–100 minutes. Snoozely uses 90 minutes as an adjustable planning estimate, not a fixed rule. Real sleep-stage timing varies, so these suggested times cannot guarantee that you will wake up refreshed.
NHLBI: sleep-cycle timing
What if a suggested bedtime has already passed?
The result will say “Already passed.” Choose an option that is still ahead of you, adjust your wake-up time if possible, or use “Sleep now” to see your options from the current time.
Will Snoozely set an alarm for me?
No. Snoozely helps you plan, but it does not set alarms or send notifications. Set your chosen wake-up time in your phone or alarm clock.
Snoozely is a planning tool for adults, not medical advice. If sleep problems persist or you feel excessively sleepy during the day, talk to a healthcare professional. About the calculator and its sources.