Sleep efficiency calculator
How much of your time in bed is actually sleep? It's the number insomnia therapists track most closely. Use typical values from the past week.
Sleep efficiency
77%
6 h 35 min asleep out of 8 h 30 min in bed
Under 80%: a lot of time lying awake. CBT-I would usually tighten the window closer to your actual sleep time, under guidance.
A CBT-I sleep window based on this week would be about 6 h 45 min in bed, for example 12:15 AM to 7:00 AM. This is for discussion with a clinician or a structured CBT-I programme, not a prescription.
Why less time in bed can mean better sleep
When sleep is poor, the instinct is to spend longer in bed to "catch" more of it. That usually backfires: extra time in bed spreads the same amount of sleep thinner, and the bed becomes linked with lying awake. CBT-I, which the American College of Physicians recommends as the first-line treatment for chronic insomnia, does the reverse. It matches time in bed to time asleep, lets sleep pressure build, and then widens the window as efficiency rises above about 85 to 90%.
Weekly adjustment rules used in CBT-I
| Average efficiency | Typical change to time in bed |
|---|---|
| ≥ 90% | Add 15–30 minutes |
| 85–89% | Keep the same |
| < 80–85% | Reduce by 15–30 minutes (never below 5.5 h) |
Track a week of nights in the sleep diary, which calculates efficiency for each night automatically.
If you've had trouble sleeping at least three nights a week for three months or more, ask your doctor about CBT-I. It is available from trained therapists and through evidence-based digital programmes.
Questions people ask
What is sleep efficiency?
Sleep efficiency is the percentage of time in bed that you actually spend asleep: total sleep time divided by time in bed, times 100. It is a core measure in cognitive behavioural therapy for insomnia (CBT-I).
What is a good sleep efficiency?
In CBT-I practice, 85% or higher is generally considered healthy for adults. Under 80% often means a lot of time lying awake. Older adults may run a little lower.
What is sleep restriction therapy?
A CBT-I technique that temporarily limits time in bed to about the amount of time you are actually sleeping, which builds sleep pressure and consolidates sleep. Time in bed is then extended in small steps as efficiency improves. It should be done with a clinician or structured programme, and never below about 5.5 hours in bed.
Who should not do sleep restriction on their own?
People with bipolar disorder, epilepsy, untreated sleep apnoea, those at risk of falls, pregnant people, and anyone whose job involves driving or safety-critical work should only do it under medical supervision, because the temporary sleepiness can be risky.
How is sleep efficiency different from sleep quality?
Efficiency is one number from time in bed and time asleep. Sleep quality also covers how rested you feel, how often you wake and how deep sleep feels. A sleep diary captures both.
Sources
- Spielman AJ, Saskin P, Thorpy MJ (1987). Treatment of chronic insomnia by restriction of time in bed. Sleep, 10(1).
- Qaseem A et al. (2016). Management of chronic insomnia disorder in adults: a clinical practice guideline from the American College of Physicians. Annals of Internal Medicine, 165(2).
- Edinger JD et al. (2021). Behavioral and psychological treatments for chronic insomnia disorder in adults: an AASM clinical practice guideline. Journal of Clinical Sleep Medicine, 17(2).