Sleep Efficiency Calculator.
Log a 7-day sleep diary, compute your sleep efficiency percentage, and get the clinical CBT-I sleep-restriction adjustment for next week.
High efficiency. Expand sleep window by 15 minutes.
Medical Disclaimer
Sleep restriction is an evidence-based component of CBT-I, but it should ideally be supervised by a sleep specialist who can rule out apnea, restless legs, and other underlying conditions. This tool is educational, not a diagnosis.
How the Math Works
The CBT-I sleep restriction protocol uses a single ratio — sleep efficiency — to decide whether to expand, hold, or restrict your sleep window each week.
- 01Time in bed (TIB). Minutes between bedtime and final rise. Crossing midnight is handled automatically by adding 24 hours if rise time is earlier.
- 02Total sleep time (TST). TIB minus the time it took to fall asleep (latency) minus minutes awake during the night (WASO).
- 03Sleep efficiency. SE = sum of TST across 7 nights / sum of TIB across 7 nights × 100.
- 04Weekly adjustment. ≥95% → bedtime 30 min earlier · 90–95% → 15 min earlier · 85–90% → no change · 70–85% → 15 min later · <70% → 15 min later + flag.
- 05Safety floor. The adjusted window can never fall below 6.0 hours. If the math would push you below, the calculator caps the bedtime and surfaces a warning.
Worked Example
Frequently Asked Questions
What is sleep efficiency?+
Sleep efficiency is the percentage of time in bed that is actually spent asleep. It is computed as total sleep time divided by total time in bed × 100. Healthy sleepers run 85–95%; chronic insomniacs often run below 80%.
What is CBT-I sleep restriction therapy?+
Sleep restriction is the most evidence-backed component of Cognitive Behavioral Therapy for Insomnia. The protocol intentionally limits time in bed to your actual sleep time, building sleep pressure and consolidating sleep. As efficiency improves, the window is gradually expanded.
Why is there a 6-hour safety floor?+
Sleep restriction below 5.5–6 hours can be counter-productive — it causes excessive daytime sleepiness and impairs the very mechanisms that help you sleep at night. Clinical CBT-I protocols never restrict bed-time below this threshold.
How do I use the weekly adjustment?+
Apply the suggested adjustment for one full week, log a new diary, and re-run the calculator. If efficiency is above 90% you can expand the window; if it drops, hold or restrict further. Most people see meaningful improvement within 2–4 cycles.
What counts as Wake After Sleep Onset (WASO)?+
WASO is the total minutes you were awake during the night after first falling asleep — not the count of awakenings, but their total duration. A single 20-minute awakening and four 5-minute awakenings both equal 20 minutes WASO.
Is this tool a substitute for therapy?+
No. CBT-I is most effective when delivered by a trained therapist who can adapt the protocol to your specific situation and rule out underlying sleep disorders. This calculator is an educational implementation of the adjustment math.