Sleep Cycle Calculator
Coming soon · #3Wake up between 90-minute sleep cycles — pick your bedtime or your alarm time.
About this tool
Planned: a sleep cycle calculator that works both ways — 'I sleep now, when do I wake?' and 'I must wake at 7, when do I sleep?' — with age-group guidance and an adjustable fall-asleep time. The softest SERP in the health set: a short blog post with 15 lines of JavaScript currently ranks first.
Searches this tool answers
People find this tool by searching for “sleep cycle calculator”. Related searches it is built for:
- what time should i wake up calculator
- sleep calculator if i go to bed now
- 90 minute sleep cycle calculator by age
Frequently asked questions
How does the 90-minute sleep cycle work?
Sleep runs in cycles of roughly 90 minutes. Waking at the end of a cycle (after 5 cycles ≈ 7.5 hours, or 6 ≈ 9 hours) usually feels easier than waking mid-cycle. It is an average rule of thumb, not an exact science.
How long do people take to fall asleep?
About 14–20 minutes for most adults — the calculator adds a fall-asleep buffer you can adjust.
Related tools
- Pregnancy Due Date & Ovulation Calculator — Estimate your due date, fertile window and pregnancy week — free and instant.
- Period Calculator — Predict your next three periods and your fertile window — private, nothing stored.
- Water Intake Calculator — How much water you actually need — by weight, activity, climate and pregnancy.