Calculadora de Ciclos de Sono
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
ciclos = floor(minutos / 90)
About this calculator
The Sleep Cycle Calculator helps you plan your bedtime to wake up at the end of a complete sleep cycle, avoiding that groggy feeling upon waking. Sleep is divided into cycles of approximately 90 minutes each, composed of light, deep, and REM stages. Waking up in the middle of a cycle can leave you feeling tired, while waking at the end tends to be more natural and refreshing.
How it works: simply input how many hours you plan to sleep. The calculator converts hours into minutes and divides that value by 90 (the average cycle duration). The result is rounded down to show how many full cycles fit into that period. For example, 6 hours (360 minutes) yields 4 complete cycles (360 ÷ 90 = 4). If you enter 7 hours, you get 420 minutes, divided by 90 gives 4.66 cycles, rounded down to 4 complete cycles.
When to use: ideal for anyone wanting to improve sleep quality, especially before important events, exams, trips, or days requiring focus. Also useful for parents planning baby naps, shift workers, or anyone who wants to wake up more refreshed. Remember that the time to fall asleep varies per person, so consider adding a 10-20 minute buffer before sleep onset.
Cautions: cycle duration can range from 70 to 110 minutes depending on the individual and the night. This calculator uses a 90-minute average, common in literature. It does not replace medical advice for sleep disorders. For best results, combine with a regular sleep routine, avoid screens before bed, and keep the environment dark and quiet.
Frequently asked questions
Why does waking up in the middle of a sleep cycle make me tired?
Waking during deep or REM sleep interrupts the natural cycle, causing sleep inertia, which is the feeling of disorientation and fatigue. Waking at the end of a cycle minimizes this effect.
How many sleep cycles are recommended per night?
Most adults need 4 to 6 complete cycles, which equals 6 to 9 hours of sleep. The ideal varies per person.
Should I include the time to fall asleep in the calculation?
Yes, if you take 15 minutes to fall asleep, add that time to the total desired hours. For example, if you want 7 hours of sleep and take 15 min, plan for 7h15min in bed.
Is the 90-minute cycle duration always accurate?
No, it can vary between 70 and 110 minutes. The 90-minute value is an average used in studies. Monitor your own rhythm to adjust.
Can this calculator help with naps?
Yes, for short naps (20-30 min) or a full cycle nap (90 min). A 90-minute nap allows passing through all stages but may cause inertia if awakened mid-cycle.