Sleep Cycle Calculator
Work backwards from your wake-up time to the bedtimes that land at the end of a 90-minute cycle, so you wake between cycles instead of mid-deep-sleep.
Open calculator →Free sleep tools
Sleep Calculators
Quick, science-backed tools for the questions our readers ask most: when to go to bed, how much sleep you owe yourself, how to beat jet lag, and which bed actually fits your room.
Sleep Debt Calculator
Add up the hours you've lost across the last week and see how long a realistic recovery plan takes.
Open calculator →Jet Lag Calculator
Get a day-by-day shift plan before you fly, plus the light and caffeine timing that speeds up adjustment.
Open calculator →Kids' Bedtime Calculator
Enter your child's age and school wake-up time for an age-appropriate bedtime window.
Open calculator →Mattress Size Calculator
Match your room dimensions, sleepers and height to the right mattress size — with exact bed footprints and walking clearance.
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