๐ Health & Fitness
Sleep Calculator
Sleep runs in cycles of roughly 90 minutes, and waking between cycles leaves you feeling far more rested than waking mid-cycle. Count backwards from your alarm in 90-minute blocks, allowing time to fall asleep.
How it works
Wake-up hour
Wake-up minute
Minutes to fall asleep
6 cycles (9h)
5 cycles (7h 30m)
4 cycles (6h)
3 cycles (4h 30m)
Sleep at 5 cycles
Frequently asked questions
How do I use the Sleep Calculator?
Fill in the fields above โ the result recalculates instantly as you type. Everything runs in your browser, so the values you enter are never collected or stored.
Is this calculator free?
Yes. It is completely free, requires no account, and works on phones, tablets and desktops.