Set the time you have to wake up and this works backwards to a bedtime, allowing for how long you take to fall asleep.
Bedtime Calculator
Works backwards from the wake time you actually have to keep — the anchor that matters most for sleep.
An honest note on “sleep cycles”: most bedtime calculators assume a tidy 90-minute cycle and promise you will wake refreshed if you time it right. Real cycles vary roughly 70 to 120 minutes, differ between people, and change across the night — so precise cycle-timing is far less reliable than it is marketed to be. We show times for common sleep durations instead, because the number that actually predicts how you feel is total sleep and a consistent wake time, not hitting a cycle boundary.
Related reading
How much sleep you actually need is in how much sleep do you need, and why a fixed wake time matters more than total hours in sleep regularity. The full protocol is in how to sleep better.
These calculators are for general education and are not medical advice or a diagnosis. Always discuss your own numbers with your doctor.