Epworth Sleepiness Scale (ESS) — daytime sleepiness.

Epworth Sleepiness Scale (ESS) — daytime sleepiness test

Validated 8-item Epworth Sleepiness Scale (Johns 1991). Scoring 0–24, four bands, plain-English interpretation, links to STOP-BANG and ISI.

Last updated: 5/2/2026 Sources verified: 5/2/2026

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How the Epworth Sleepiness Scale works

ESS lists 8 everyday situations that vary by how passive they are — reading is more passive than driving, lying down more passive than talking. For each, you rate your usual chance of dozing off in recent times on a 0–3 scale: would never doze, slight chance, moderate chance, high chance. The total is 0–24.

The point is not to measure a single sleepy day. ESS asks about your usual pattern over recent weeks. That makes it useful for spotting chronic sleepiness — the kind that points toward sleep apnea, untreated insomnia, narcolepsy, or long-term sleep debt.

What your score means

Score	Band
0–10	Normal daytime sleepiness
11–12	Mild excessive daytime sleepiness
13–15	Moderate excessive daytime sleepiness
16–24	Severe excessive daytime sleepiness

A score of 16+ combined with snoring or witnessed breathing pauses strongly suggests sleep apnea. That deserves a sleep-doctor visit and likely a sleep study.

When ESS is useful — and when it is not

Useful for: persistent daytime sleepiness over weeks, screening before a sleep-medicine visit, tracking response to treatment (CPAP, schedule changes, weight loss).

Not useful for: one bad night of sleep, one stressful week, jet lag, sleepiness that only appears in specific situations (e.g., only after lunch).

Everyone has tired days. ESS measures the chronic pattern over weeks. Use it when sleepiness has been a theme for a while, not after a single rough Tuesday.

Sleepiness is not the same as fatigue

Fatigue is heaviness, low energy, or feeling worn out. Sleepiness is dozing off when you should be awake. People with depression often have fatigue with normal ESS scores. People with sleep apnea often have high ESS even when they say they sleep enough hours. The distinction matters because the treatments are different.

If your main problem is feeling tired without actually dozing, PHQ-9 (depression) or GAD-7 (anxiety) may be more useful than ESS.

Common causes of excessive daytime sleepiness

Sleep apnea — most common in the moderate-to-severe range, especially with snoring or witnessed breathing pauses. STOP-BANG is the screener.
Insomnia — trouble falling or staying asleep. The Insomnia Severity Index (ISI) is the right tool.
Depression — fatigue with sleep changes; PHQ-9 helps sort it out.
Medication side effects — antihistamines, some blood-pressure drugs, antidepressants, opioids, anti-seizure meds. A quick check with your pharmacist can clarify.
Narcolepsy — much rarer, but worth ruling out at very high scores. Sleep doctors confirm with specific testing.
Chronic sleep deprivation — the simplest cause. The fix is more sleep.

STOP-BANG — sleep-apnea screener (8 questions, 2 minutes).
ISI — Insomnia Severity Index for trouble falling or staying asleep.
PHQ-9 — depression screen, useful when fatigue is the main feeling.

Privacy

All scoring runs in your browser. We never see, log, or store your individual answers. Only an anonymous event is sent to a privacy-respecting analytics service.

Licence

The Epworth Sleepiness Scale was developed by Murray W. Johns and is widely used in clinical practice. Published in Sleep 1991;14(6):540-545.

Frequently asked questions

What does the Epworth Sleepiness Scale measure?

ESS measures the chronic likelihood of dozing off in 8 everyday situations — reading, watching TV, sitting in a meeting, riding in a car, lying down in the afternoon, talking, after lunch, and stopped in traffic. It captures a pattern over recent weeks, not one bad night. Scores range 0–24 and group into normal (0–10), mild (11–12), moderate (13–15), and severe (16–24) excessive daytime sleepiness.

Is a high Epworth score the same as sleep apnea?

No. ESS is a screen for excessive daytime sleepiness — it flags that something is off with daytime alertness, but does not name the cause. Sleep apnea is the most common cause in the moderate-to-severe range, especially with snoring or witnessed breathing pauses. Other causes include narcolepsy, chronic sleep deprivation, depression, and medication side effects. STOP-BANG is the next step if apnea is suspected.

Sleepiness vs fatigue — what's the difference?

Fatigue is feeling tired, heavy, or low on energy without necessarily dozing off. Sleepiness is the tendency to actually fall asleep when you should be awake. ESS measures sleepiness specifically. People with depression often have fatigue but normal ESS; people with sleep apnea often have high ESS even when they say they sleep enough hours.

How often should I retake ESS?

ESS reflects the past few weeks of daytime alertness. Retesting weekly is too frequent. Useful retest intervals: 4 weeks after a sleep-habit change (cutting alcohol, fixing schedule, treating snoring), 6–12 weeks after starting CPAP, or anytime your sleep pattern changes meaningfully — new shift work, partner snoring, weight change, new medication.

Does my data leave the device?

No. All scoring runs entirely in your browser. Only an anonymous event (locale, severity band) is sent to a privacy-respecting analytics service. Your individual answers never leave the device.