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STOP-BANG Calculator

The STOP-BANG questionnaire is an evidence-based screening tool used globally to identify individuals at risk for obstructive sleep apnea (OSA). By evaluating eight key factors—snoring, daytime tiredness, observed breathing pauses, high blood pressure, BMI, age, neck circumference, and biological sex—the tool generates a risk score that guides clinical decision-making. Primary care physicians, sleep specialists, and anaesthesiologists rely on this assessment to flag patients who may need formal sleep studies or intervention.

Last updated:

Creators Małgorzata Koperska, MD
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Understanding Obstructive Sleep Apnea

Obstructive sleep apnea occurs when throat muscles relax excessively during sleep, narrowing or collapsing the airway. This blockage forces the brain to arouse the sleeper to restore breathing, fragmenting sleep and reducing oxygen saturation. These episodes can happen dozens of times per hour in severe cases.

Three main types exist: obstructive sleep apnea (OSA), caused by physical airway collapse; central sleep apnea (CSA), where the brain fails to signal breathing muscles; and mixed apnea, combining both mechanisms. OSA accounts for roughly 85% of all sleep apnea diagnoses and is strongly associated with cardiovascular events, hypertension, atrial fibrillation, and increased mortality if left untreated.

STOP-BANG Scoring Formula

The STOP-BANG score sums eight binary items, each contributing 1 point if present. Your final score ranges from 0 to 8 and indicates OSA risk stratification:

STOP-BANG Score = S + T + O + P + B + A + N + G

where:

S = Snoring (yes = 1)
T = Tired during day (yes = 1)
O = Observed apneas (yes = 1)
P = High blood Pressure (yes = 1)
B = BMI > 35 kg/m² (yes = 1)
A = Age > 50 years (yes = 1)
N = Neck circumference > 40 cm (M) or > 37 cm (F) (yes = 1)
G = Gender male (yes = 1)

BMI = mass (kg) ÷ height² (m²)

  • S — Presence of habitual snoring or reports from bed partner
  • T — Daytime somnolence, fatigue, or morning unrefreshed feeling
  • O — Witnessed apneic episodes or gasping during sleep
  • P — Systolic blood pressure >140 mmHg or diastolic >90 mmHg
  • B — Body mass index exceeding 35 kg/m²
  • A — Age 50 years or older
  • N — Neck circumference (measured at cricoid level, supine)
  • G — Biological sex (male = 1 point)
  • BMI — Body mass index in kilograms per metres squared

Risk Stratification and Clinical Interpretation

STOP-BANG divides OSA risk into three tiers based on your cumulative score:

  • Score 0–2 (Low risk): Unlikely to have clinically significant OSA. General practitioner monitoring and lifestyle modification may suffice.
  • Score 3–4 (Intermediate risk): Moderate likelihood of OSA. A sleep study (polysomnography or home sleep apnea test) is often recommended before treatment.
  • Score 5–8 (High risk): Strong probability of OSA. Urgent formal diagnosis and initiation of continuous positive airway pressure (CPAP) or alternative therapy is typically warranted.

This scoring system demonstrates high sensitivity (up to 90%) for detecting moderate-to-severe OSA, making it particularly useful in pre-operative assessment and primary care triage.

Key Risk Factors Behind the Score

Each STOP-BANG component reflects a distinct pathophysiological pathway or epidemiological association with OSA:

  • Snoring and observed apneas: Direct audible signs of airway obstruction and breathing interruption.
  • Daytime fatigue: Results from fragmented sleep architecture and oxygen dips during nocturnal apneic events.
  • Hypertension: Both a consequence of untreated OSA and an independent risk marker; bidirectional relationship.
  • Elevated BMI: Excess soft tissue in the neck and pharynx narrows the airway lumen.
  • Age over 50: Pharyngeal muscle tone declines with advancing age, increasing collapse risk.
  • Large neck circumference: Directly reduces upper airway patency independent of overall body weight.
  • Male sex: Hormonal factors and muscle distribution favour airway obstruction in men.

Important Considerations When Using STOP-BANG

The STOP-BANG questionnaire is a screening tool, not a diagnostic test—keep these practical points in mind:

  1. Self-reported bias in symptom endorsement — Patients may underestimate snoring or daytime tiredness, especially if they live alone or attribute fatigue to work stress. Bed partner corroboration significantly improves accuracy. Always ask family members about sleep behaviour when possible.
  2. Neck circumference measurement technique matters — Measure at the level of the cricoid cartilage (the bony prominence at the front of the neck) while sitting upright, not tilted back. Incorrect technique can shift your risk category and delay or expedite referral for sleep study.
  3. BMI limitations in muscularity and ethnicity — BMI does not distinguish muscle from fat. Athletic individuals with high BMI may be misclassified as higher risk. Conversely, some ethnic populations (South Asian, East Asian) show OSA at lower BMI thresholds, so clinical judgment remains essential.
  4. Score does not replace polysomnography — A high STOP-BANG score predicts OSA likelihood but cannot determine severity, apnea-hypopnea index, or oxygen desaturation patterns. Formal sleep study remains the gold standard for diagnosis and therapy titration.

Frequently Asked Questions

What does each letter in STOP-BANG represent?

STOP-BANG is an acronym: S stands for snoring, T for tired (daytime somnolence), O for observed apneas, P for pressure (high blood pressure), B for BMI greater than 35, A for age over 50, N for neck circumference, and G for gender (male). Each item contributes one point if present, yielding a total between 0 and 8. The tool was designed to be memorable and easy to administer in busy clinical settings.

How reliable is STOP-BANG for diagnosing sleep apnea?

STOP-BANG is a sensitive screening instrument with reported sensitivity around 90% for detecting moderate-to-severe OSA, but it cannot diagnose the condition on its own. False positives do occur—for example, an overweight, snoring 55-year-old man may score high yet have mild or no sleep apnea. Conversely, some individuals with significant OSA may score in the intermediate range. Polysomnography (in-laboratory sleep study) or home sleep apnea testing provides definitive diagnosis and quantifies severity.

Can STOP-BANG be used in children?

Standard STOP-BANG was developed and validated in adults and is not recommended for paediatric populations. Children present different anatomical and physiological profiles; enlarged adenoids and tonsils, rather than obesity and age, drive many cases of childhood OSA. A separate paediatric sleep apnea screening tool (such as the Paediatric Sleep Questionnaire) is more appropriate for children.

What happens if I score 5 or higher on STOP-BANG?

A score of 5–8 indicates high OSA risk and warrants prompt evaluation. Your primary care physician or sleep specialist will typically order polysomnography or a home sleep apnea test. If OSA is confirmed, treatment options include CPAP therapy (the gold standard for moderate-to-severe cases), oral appliances, lifestyle changes (weight loss, positional therapy), or in select cases, surgery. Early intervention reduces cardiovascular complications and improves daytime functioning.

Does weight loss improve a high STOP-BANG score?

Yes. Sustained weight loss of 10–15% can improve or resolve OSA symptoms in many people, particularly those with mild-to-moderate disease. Excess weight narrows the airway, so reducing BMI below 35 eliminates one STOP-BANG point and often improves the underlying physiology. However, weight loss alone may not be sufficient for severe cases, and combined treatment (e.g., CPAP plus lifestyle change) is often necessary.

Is STOP-BANG different from other OSA screening tools?

STOP-BANG is among the most widely used, but alternatives exist. The Epworth Sleepiness Scale focuses on subjective daytime somnolence; the Berlin Questionnaire emphasizes snoring and witnessed apneas; the STOP questionnaire (without BANG) is simpler but less comprehensive. STOP-BANG's advantage is its brevity (8 yes/no items), strong sensitivity, and ease of administration in non-specialist settings, making it popular in primary care, anaesthesia, and occupational health screening.

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