Sleep efficiency is the percentage of your time in bed that you actually spend asleep. Use your best estimates from last night, or use averages from your sleep diary.
What is sleep efficiency?—
Sleep efficiency describes how much of your time in bed was spent asleep. It is a description of one night, not a diagnosis, and it does not tell you what your sleep window should be. This tool will not set a schedule for you.
Single nights vary a great deal — a late meal, a noisy street, an early start or an unusual day can move this number by ten points or more. Patterns across a week or two are generally far more informative than any one night, which is what a diary is for.
What does sleep efficiency mean?
Time in bed (23:00 → 07:00) = 480 min
Sleep onset latency (23:00 → 23:35) = 35 min
Awake during the night = 30 min
Awake after final waking (06:30 → 07:00) = 30 min
Estimated total sleep = 480 − 35 − 30 − 30 = 385 min (6 hr 25 min)
Sleep efficiency = 385 ÷ 480 × 100 = 80.2%, displayed as 80%
The measure is used in insomnia care because it captures something an "hours slept" figure misses: the relationship between time spent in bed and time actually asleep. Two people sleeping six hours are in very different situations if one spent six and a half hours in bed and the other spent nine.
It is also the number that cognitive behavioural therapy for insomnia (CBT-I) works with, because a low figure points at time awake in bed rather than at an inability to sleep. How that information is used — including any change to when you go to bed or get up — is a decision for a diary and, where possible, a clinician. Reading a percentage here is not a reason to change your sleep schedule tonight.
Related resources
Evidence and medical information
This page does not currently cite external sources or studies.
This tool has not been medically reviewed.
The Sleep Record is an educational resource. This calculator estimates a descriptive figure from your own answers. It does not diagnose insomnia or any other condition, does not recommend sleep restriction, does not set a sleep window, and is not a substitute for care from a qualified clinician.