Find Your Ideal Bedtime
For Any Wake-Up Time
You need to wake up at a specific time — this calculator works backwards to find bedtimes that complete full 90-minute cycles before your alarm. No mid-cycle grogginess. No guesswork.
Calculate Your Bedtimes
Enter your required wake-up time and how long it typically takes you to fall asleep.
Choosing the right bedtime is about cycle completion, not just total hours. Your brain cycles through four sleep stages every ~90 minutes: N1 (light), N2 (core), N3 (deep slow-wave), and REM. Waking mid-cycle — especially mid-N3 deep sleep — triggers sleep inertia: 20–40 minutes of heavy grogginess that no amount of coffee fully reverses.
By going to bed at a cycle-aligned time, your alarm falls at a natural cycle end when you’re in light N1 sleep and physiologically ready to wake. The difference is immediate — you open your eyes feeling alert rather than dragged out of unconsciousness.
Research also shows bedtime consistency (varying by under 30 minutes) improves sleep quality independently of duration. A regular bedtime anchors your circadian rhythm, improving melatonin onset timing and reducing how long it takes to fall asleep.
4 Common Bedtime Mistakes
- Going to bed before you feel sleepy. Lying awake in bed teaches your brain to associate the bed with wakefulness rather than sleep — the mechanism behind conditioned insomnia anxiety. Only go to bed when genuinely drowsy.
- Varying bedtime by more than 30 minutes regularly. Your circadian rhythm regulates melatonin release on a ~24-hour schedule. Shifting bedtime more than 30 minutes desynchronises this clock, reducing sleep quality and increasing onset time — even when total hours are the same.
- Prioritising round hours over cycle alignment. 7.5 hours (5 complete cycles) consistently beats 7 hours (4.67 cycles — a mid-cycle wake) for morning alertness. The extra 30 minutes of 8 hours can actually make you feel worse if it lands mid-cycle.
- Using the same bedtime regardless of wake time. Always work backwards from your required wake time, not forwards from a fixed bedtime. Your wake time drives the cycle calculation — bedtime follows from it.
Frequently Asked Questions
What is the best time to go to bed?
There is no single universal best bedtime — it depends on your required wake time, your sleep need (7–9 hours for most adults), and your chronotype. For a 7am wake time with 14 minutes to fall asleep, the cycle-aligned bedtimes are: 9:16pm (6 cycles, 9h), 10:46pm (5 cycles, 7.5h — recommended for most adults), 12:16am (4 cycles, 6h — minimum). The 10:46pm option aligns with typical adult melatonin onset timing and meets NSF recommendations for adults aged 18–64. Use the calculator above to generate your personalised bedtimes based on your actual wake time and sleep latency.
Does it matter if I go to bed at the same time every night?
Yes — sleep timing consistency significantly affects quality. The circadian rhythm regulates melatonin release and core body temperature on a roughly 24-hour schedule. When bedtime shifts by more than 30 minutes regularly, this biological clock desynchronises, making it harder to fall asleep and reducing deep sleep quality even when total sleep hours remain constant. Studies on social jetlag — the bedtime shift between weekdays and weekends — show measurable impairments in mood, metabolism, and cognitive performance. Aim to keep your bedtime within a 30-minute window seven nights a week, including weekends. Your alarm time is the anchor; let bedtime follow consistently from it.