Sleep Calculator

Find the best time to go to bed or wake up based on your sleep cycles.

Sleep Planner

Optimize your REM cycles for a refreshed morning.

What time do you need to wake up?

The 90-Minute Rule

A typical sleep cycle is 90 minutes. Better to wake up at the end of a cycle than in the middle. We add 15 mins for falling asleep.

Recommended Bedtimes

💡 Waking up during REM sleep can leave you feeling groggy and tired (sleep inertia). Waking between cycles ensures you feel alert.

Understanding the Sleep Cycle Calculator

Optimize your wake-up time or bedtime based on natural 90-minute sleep cycles to wake up feeling refreshed.

Guide

How to use the Sleep Cycle Calculator

1Choose 'I want to wake up at...' to find the best bedtime.
2Choose 'I plan to sleep at...' to find the best wake-up time.
3Set your desired time.
4Review the suggested times. Aim for 5-6 cycles for optimal rest.

Applications

Common Use Cases

Productivity: Waking up alert for an early meeting.

Health: Ensuring consistent 7.5-9 hours of sleep.

Shift Work: Planning naps (1 cycle = 1.5 hrs) efficiently.

The Maths Behind the Calculation

Time ± (90 minutes × N) + 15 min fall-asleep time

Human sleep consists of ~90-minute cycles. Waking up at the end of a cycle (REM stage) usually results in feeling more refreshed than waking up in the middle of deep sleep.

Knowledge Base

Frequently Asked Questions

How long is a sleep cycle?

On average, a sleep cycle lasts about 90 minutes, moving through light sleep, deep sleep, and REM sleep.

Does this include time to fall asleep?

Yes, the calculator adds a default 15 minutes to allow for falling asleep.

Regional Notice: United States

"Federal tax estimates are based on 2024 brackets. Consult a tax professional for official filing."

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