Free, no sign-up
Sleep tools
Small tools for the practical parts of sleep. Each one shows its arithmetic and cites what it is based on, because a calculator that hides its assumptions is just a confident guess.
Sleep Calculator
Pick a wake-up time and count back through full sleep cycles to a realistic bedtime window.
Caffeine Cutoff Calculator
Enter your bedtime and see when to switch to decaf, based on how long caffeine actually lingers in the body.
Breathing Pacer
A visual guide for 4-7-8, box, and coherent breathing — follow the circle, slow your breath, wind down for bed.
More from Slumber Studios
Two of our sleep tools are big enough to live on their own sites. Both are free, both start with one tap, and neither asks you to sign up.