Find the best times to go to bed based on 90-minute sleep cycles so you wake up feeling refreshed.
Find the best times to go to bed based on 90-minute sleep cycles so you wake up feeling refreshed.
Bedtime = Wake Time – (Cycles × 90 min) – 15 min
Wake at 7:00 AM → Best bedtimes: 9:45 PM (6 cycles), 11:15 PM (5 cycles).
Enter your values in the fields above and click "Calculate" to get instant results. All calculations happen in your browser — nothing is sent to any server.
What is Sleep Calculator?
Find the best times to go to bed based on 90-minute sleep cycles so you wake up feeling refreshed.
What formula does this use?
This calculator uses: Bedtime = Wake Time – (Cycles × 90 min) – 15 min
Is this calculator free?
Yes! All calculators on CalcNest AI are 100% free with no account required.
Is my data safe?
Absolutely. All calculations run locally in your browser. We never store or transmit your input data.