Sleep Calculator
Find your ideal bedtime or wake-up time based on 90-minute sleep cycles — the science-backed method for waking up refreshed.
How sleep cycles work
Each sleep cycle lasts approximately 90 minutes and includes light sleep, deep sleep, and REM sleep stages. Waking up at the end of a cycle — rather than in the middle — means you surface from light sleep, feeling naturally alert and refreshed instead of groggy.
💤 14–17 hours (Newborns)
Newborns spend most of their time sleeping, with sleep distributed across the day.
🧒 9–11 hours (School age)
Growing children need more sleep for cognitive development and memory consolidation.
🧑 8–10 hours (Teenagers)
Teenage brains are still developing. Early school starts conflict with natural sleep biology.
🧑💼 7–9 hours (Adults)
Most adults function best with 7–9 hours — equivalent to 5–6 complete sleep cycles.
👴 7–8 hours (Seniors 65+)
Sleep becomes lighter and shorter with age. Good sleep hygiene becomes even more important.