Free Sleep Calculators & Tools — Bedtime, Nap & Sleep Schedule
Find your ideal bedtime, wake-up time, and sleep schedule using science-backed 90-minute sleep cycle calculations. 8 free tools — no signup, no ads, works on any device.
All Sleep Tools
8 toolsWhy Sleep Cycles Matter
Sleep is not one long block — it's a series of 90-minute cycles, each containing light sleep, deep (slow-wave) sleep, and REM sleep. Waking up mid-cycle causes sleep inertia — the groggy, disoriented feeling that can last for hours.
Our sleep calculators align your schedule to natural cycle boundaries so you wake at the lightest sleep stage, feeling alert and refreshed — even if you slept fewer total hours.
Try the Sleep Calculator →Free Sleep Calculators for Every Sleep Problem
Whether you struggle to fall asleep, wake up groggy, work night shifts, or are trying to fix a newborn's schedule, there is a specific calculator for your situation. Our sleep tools cover every major sleep challenge: finding the right bedtime based on sleep cycles, calculating how much sleep debt you have built up, determining when to stop drinking caffeine, recovering from jet lag, and assessing your overall sleep quality with a clinically validated quiz.
How Sleep Calculators Work — The 90-Minute Cycle Science
All sleep timing calculators on this site are based on the 90-minute sleep cycle model, supported by decades of polysomnography research. A complete sleep cycle moves through four stages: N1 (light sleep), N2 (consolidated sleep), N3 (deep slow-wave sleep), and REM (rapid eye movement sleep). Waking at the end of a complete cycle — when you are in the lightest sleep stage — results in feeling refreshed. Waking mid-cycle, particularly during N3 deep sleep, causes sleep inertia.
Sleep Tools for Shift Workers, Parents, and Students
Standard sleep advice assumes a 9-to-5 schedule — but shift workers, new parents, and students face fundamentally different sleep challenges. Night shift workers need to optimise a daytime sleep window. New parents need to understand infant sleep cycles to plan their own rest. Students pulling late nights need to know the minimum effective sleep duration before an exam.