Wake up on the right cycle.
Free sleep calculators for bedtimes, wake times, sleep debt, caffeine timing, and naps — all built around 90-minute sleep cycles. Estimates for general use, not medical advice.
Bedtime Calculator
When to go to bed for your wake time — lands you at the end of a 90-minute cycle so you rise refreshed.
Find your bedtimeWake Time Calculator
Best times to wake from a bedtime — every cycle boundary where waking feels natural.
Find wake timesSleep Debt Calculator
The hours of sleep you owe yourself — running tally across the week and how long to pay it back.
Calculate sleep debtCaffeine Cutoff Calculator
How much caffeine is still in your system at bedtime — and the ideal last-cup window by bedtime.
Find your cutoffSleep By Age Calculator
Recommended sleep hours by age — newborn through adult, with personalized target ranges.
See sleep by ageNap Calculator
Best nap length and when to wake — power nap, full cycle, or long recovery nap timed to your schedule.
Plan a napGuides
Plain-English explainers: how sleep cycles work, how much sleep you actually need, and how caffeine affects sleep.