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Interactive Sleep Cycle Calculator

Health

Calculate the optimal time to go to bed or wake up refreshed.

ttb run sleep-calculator

I need to wake up at:

:

Optimal Bedtimes

9:45 PM6 Sleep Cycles
9Hours
11:15 PM5 Sleep Cycles
7.5Hours
12:45 AM4 Sleep Cycles
6Hours
2:15 AM3 Sleep Cycles
4.5Hours

A good night's sleep consists of 5-6 complete sleep cycles. Waking up in the middle of a cycle leaves you feeling groggy, so it's better to sleep less and wake up between cycles!

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How to Use Sleep Cycle Calculator

Input the exact time your alarm is set to wake you up in the morning. Adjust the minutes required for you to fall asleep (typically 15). The optimal bedtimes calculator will work backward in 90-minute sleep cycles, suggesting the exact time you must fall asleep to wake up refreshed instead of groggy.

1

Enter your parameters

Configure the inputs for the Sleep Calculator according to your specific needs.

2

View real-time results

The utility instantly processes your request and displays the calculated outputs directly in your browser.

3

Copy or Download

Click the copy icon next to the final output to instantly grab the result, or export it if applicable.

Frequently Asked Questions

Why are the sleep cycles 90 minutes?+
Human sleep architecture operates in roughly 90-minute phases, moving from light sleep, to deep sleep, to REM (Rapid Eye Movement). If your alarm wakes you up in the middle of Deep Sleep, you will suffer from "sleep inertia" and feel incredibly tired.
Is sleeping 6 hours better than sleeping 7 hours?+
Potentially! 6 hours is exactly four 90-minute sleep cycles. Waking up naturally at the end of a cycle often leaves you feeling substantially more rested than sleeping an extra hour (7 hours total) and being jolted awake by an alarm deep inside cycle number five.
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