Sleep Calculator
Plan bedtime from wake time, desired sleep and your estimated time to fall asleep.
Formula
Bedtime=wake time−sleep duration−latency; day shift −1 means the previous day.
Wake time (24-hour) = 07:00 · Desired sleep (hours) = 8 · Time to fall asleep (minutes) = 15
How to use
- Choose your wake time.
- Enter sleep hours in quarter-hour steps and latency.
- Read bedtime and day shift.
Examples
- Wake 07:00, sleep 8 hours, latency 15 minutes → 22:45 the previous day.
Frequently asked questions
Does it time 90-minute cycles?
No. NHLBI describes cycles of roughly 80–100 minutes; this tool does not predict stages.
Does time in bed guarantee sleep?
No. It is planning arithmetic; awakenings and individual needs are not predicted.
Is this medical advice?
For reference only; it does not replace a clinician.
Sources
Updated: