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Sleep calculator

Short sleep makes dieting harder: more hunger, worse training. Pick your wake-up time to see good bedtimes.

Results

6 sleep cycles (9.0 h)
Lights out 9:15 PM
5 sleep cycles (7.5 h)
Lights out 10:45 PM
4 sleep cycles (6.0 h)
Lights out 12:15 AM

Assumes about 15 minutes to fall asleep and 90-minute cycles. Most adults need 7–9 hours.

How to use it

  1. Enter your wake-up time.
  2. Pick a bedtime for 5–6 cycles.
  3. Keep it consistent, including weekends.

Read next

FAQ

Does sleep affect belly fat?

Poor sleep is linked to more hunger and less muscle retention on a diet, which makes fat loss harder.

Are sleep cycles always 90 minutes?

They vary, roughly 80–110 minutes. Treat the times as guides.

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