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.
What sleep efficiency is.
Sleep efficiency (SE) is the fraction of time in bed actually spent asleep: SE = total sleep time / time in bed × 100. Healthy sleepers run at 85–95%. People with insomnia spend long stretches in bed awake — falling asleep slowly (sleep onset latency), waking through the night (wake after sleep onset, WASO), or both — and run SE in the 60–75% range.
The counter-intuitive insight from sleep medicine: lying in bed awake makes insomnia worse, not better. The bed becomes a conditioned cue for wakefulness and frustration. Sleep restriction therapy compresses time in bed to match actual sleep, which forces SE up, consolidates sleep, and rebuilds the bed–sleep association.
How the weekly adjustment works.
After a 7-day sleep diary, the protocol adjusts time in bed based on average SE: ≥95% means time in bed can expand by ~15 minutes; 90–95% holds at the current window; 85–90% holds with continued monitoring; below 85% requires further restriction. A hard 6-hour floor is standard — restricting below that produces excessive daytime sleepiness and is unsafe to drive on.
This is the protocol used clinically in cognitive behavioral therapy for insomnia (CBT-I). Trauer et al. (2015) meta-analyzed 20 randomized trials and found CBT-I produced large, durable improvements in sleep onset latency, WASO, and SE — effect sizes that match or exceed pharmacotherapy and persist long after treatment ends.
Why CBT-I is the first-line treatment.
The American College of Physicians’ 2016 clinical practice guideline (Qaseem et al.) names CBT-I as the first-line treatment for chronic insomnia in adults — before any sleep medication. The reasoning: hypnotics produce short-term improvements but lose efficacy over months, carry dependence and next-day cognitive risk, and do not address the conditioned arousal that drives chronic insomnia. CBT-I produces smaller week-one effects but larger long-term ones.
Sleep restriction is the highest-yield component of CBT-I, alongside stimulus control (use the bed only for sleep), cognitive restructuring (challenge catastrophic thoughts about lost sleep), and sleep hygiene. The other components reinforce the gains but rarely produce them alone.
How to actually run the protocol.
Log seven consecutive nights honestly — bedtime, time you tried to sleep, latency in minutes, number and duration of awakenings, final rise time. Calculate the average and apply the bracket adjustment. Hold the new window for one full week before adjusting again. Expect the first 1–2 weeks to feel worse — sleep deprivation is a feature of the protocol, and it is what drives the consolidation.
If sleep efficiency does not improve after 3–4 weeks of strict adherence, or if daytime sleepiness becomes unsafe, work with a behavioral sleep medicine clinician. Self-directed CBT-I is effective for many but not all cases of chronic insomnia.
- Trauer JM, Qian MY, Doyle JS, Rajaratnam SM, Cunnington D. (2015). Cognitive behavioral therapy for chronic insomnia: a systematic review and meta-analysis. Ann Intern Med, 163(3), 191–204.
- Qaseem A, Kansagara D, Forciea MA, Cooke M, Denberg TD; Clinical Guidelines Committee of the American College of Physicians. (2016). Management of chronic insomnia disorder in adults: a clinical practice guideline from the American College of Physicians. Ann Intern Med, 165(2), 125–133.
- Spielman AJ, Saskin P, Thorpy MJ. (1987). Treatment of chronic insomnia by restriction of time in bed. Sleep, 10(1), 45–56.
Low sleep efficiency often tracks evening cortisol. The reset targets the circadian levers that fix it.
Get the guide →For education, not medical advice. Results are estimates, not a diagnosis — discuss any abnormal value or health concern with a qualified clinician.
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