How does the sleep calculator work?
It counts in 90-minute sleep cycles — the rhythm your brain naturally follows all night — and adds about 15 minutes for falling asleep. Waking at the end of a cycle, when you're in light sleep, feels dramatically easier than an alarm that lands in deep sleep.
What time should I go to bed?
Work backward from your wake-up time in 90-minute steps and add 15 minutes to fall asleep. For a 6:30 AM alarm, that means about 9:15 PM for six cycles (9 hours) or 10:45 PM for five cycles (7.5 hours). Both beat going to bed at a random hour and waking mid-cycle.
Why do I wake up tired after 8 hours of sleep?
Because eight hours isn't a multiple of 90 minutes. An 11:00 PM bedtime with a 7:00 AM alarm often drops you into the middle of a deep-sleep phase — and waking from deep sleep causes sleep inertia, the heavy grogginess that coffee can't fix. Shifting the same amount of sleep to end on a cycle boundary is frequently all it takes.
Does the exact bedtime matter more than consistency?
No. A consistent wake time is the strongest signal your body clock gets — stronger than any perfectly-timed single night. Use the calculator to pick a realistic target, then hold your wake time steady within 30 minutes, even on weekends. Your bedtime will start arriving naturally.
A calculator can't wake you up. Volyia can.
This page tells you the right time — the app makes it actually happen. Volyia's Smart Wake alarm can't be swiped away, the one-minute Night Ritual winds you down on schedule, and your Rhythm Score shows the payoff day by day.
