Sleep Calculator

Find out what time to go to sleep or wake up to feel refreshed by aligning with natural 90-minute REM sleep cycles.

How to use this calculator

1. Pick goal.
2. Enter target time.
3. Read cycle options.

Formula & method

90-Min Sleep Cycle Model

Time = Target ± (Cycles × 90 min) ± 14 min

Sleep latency accounted.

Example

Wake at 7:00 AM → sleep at 11:16 PM (5 cycles).

Key insights

• Sleep cycles last ~90 minutes.

How to interpret your result

Cycles

5 cycles = 7.5 hours sleep.

Frequently asked questions

How long is a cycle?

90-110 minutes.

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