Sleep Calculators
Free sleep calculators from the Yawnder review team. No sign-up, no email, nothing stored — every one of these runs in your browser and gives you a schedule you can actually act on tonight.
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Sleep cycle calculator
Enter your wake-up time or bedtime to see estimated schedules using sleep-cycle intervals. The calculator cannot determine which sleep stage you will wake from.
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Sleep debt calculator
Log the last seven nights and see how many hours you are actually down — plus a realistic catch-up plan that will not wreck next week.
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Jet lag calculator
Tell us your flight direction and time-zone shift and get a day-by-day pre-travel plan so you land closer to local time.
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Kids’ bedtime calculator
Enter your child’s age and school wake-up time for a bedtime inside the recommended sleep range for that age group.
How to use these together
Before replacing a mattress, consider whether inconsistent sleep timing is part of the problem. Start by estimating a sleep window with the sleep cycle calculator, check whether you are carrying a deficit with the sleep debt calculator, hold the schedule for two weeks, and only then judge whether your bed is the problem.
The calculations use an illustrative 90-minute interval and an adjustable allowance for falling asleep. Actual sleep-cycle lengths and time to fall asleep vary from person to person and night to night. A schedule calculator cannot predict light versus deep sleep or guarantee an easier wake-up.
Cycle length varies by person and by night, so treat every time below as a target to test for a week, not a prescription. Adults generally need 7–9 hours; consistently landing under 7 is where the measurable performance and health costs start.
What these calculators do not do
They are scheduling tools, not diagnostics. If you sleep a full night and still wake unrefreshed, snore heavily, gasp or stop breathing in your sleep, or fall asleep during the day, that pattern belongs in front of a doctor — no bedtime math will resolve sleep apnea, insomnia or restless legs. Nothing on this page is medical advice.
Once the schedule is right, the bed has to hold up its end
A calculator can help you plan your schedule, but it cannot fix a mattress that traps heat, sags in the middle or wakes you every time your partner rolls over. If you are waking up sore or hot even on a sensible schedule, that is a hardware problem, not a scheduling one.
Not sure which bed fits you: use the mattress finder, compare specs side by side in the comparison tool, or read how we test.