Calculate your sleep efficiency before starting
Track your actual sleep time versus time in bed for one week — the gap is the starting point for restriction.
Key takeaways
- What it is: Track your actual sleep time versus time in bed for one week — the gap is the starting point for restriction.
- Why it works: Sleep efficiency (actual sleep time divided by time in bed, as a percentage) is the key metric for sleep restriction therapy. A healthy sleeper has efficiency around 85–90%. An insomniac commonly has 60–70% efficiency: spending eight hours in bed but sleeping only five or six. The gap represents time spent awake in bed, which conditions the brain to associate the bed with wakefulness and arousal — the core maintaining mechanism of chronic insomnia.
- Evidence: Established clinical or therapeutic practice.
- Avoid: Estimating from memory rather than prospective logging — memory of sleep is notoriously inaccurate, and insomniac patients systematically underestimate their sleep time.
Why it works
Sleep efficiency (actual sleep time divided by time in bed, as a percentage) is the key metric for sleep restriction therapy. A healthy sleeper has efficiency around 85–90%. An insomniac commonly has 60–70% efficiency: spending eight hours in bed but sleeping only five or six. The gap represents time spent awake in bed, which conditions the brain to associate the bed with wakefulness and arousal — the core maintaining mechanism of chronic insomnia.
How to do it
- 1For seven days, log the time you got into bed, the estimated time you fell asleep, any wake periods, and the time you got up.
- 2Calculate: (total sleep time / total time in bed) × 100 = sleep efficiency percentage.
- 3Average across the week to get your baseline efficiency.
What the evidence says
Clinical practiceSleep efficiency as a metric for insomnia severity is standard in sleep medicine; the baseline calculation is the entry point for all CBT-I sleep restriction protocols.
Honest caveat: Self-report sleep logs are imprecise; they are sufficient for clinical guidance but will not capture exact sleep architecture. Consumer wearables add light-effort objective data but their sleep-stage accuracy is limited.
- — Spielman, Saskin & Thorpy (1987), treatment of chronic insomnia by restriction of time in bed, Sleep
Common mistake
Estimating from memory rather than prospective logging — memory of sleep is notoriously inaccurate, and insomniac patients systematically underestimate their sleep time.
IX Coach provides a simple seven-day sleep log and calculates your baseline efficiency automatically, identifying the gap you need to close before the restriction phase.
Practice this with IX Coach →