CURB-65 Score Calculator (Pneumonia Severity)
Community-acquired pneumonia severity and 30-day mortality with CURB-65 — confusion, urea, respiratory rate, blood pressure, age 65 — with outpatient, ward or ICU guidance and the CRB-65 variant.
How it works
One point each: Confusion, Urea > 7 mmol/L, Respiratory rate ≥ 30, BP systolic < 90 or diastolic ≤ 60, age ≥ 65. 0–1 low, 2 moderate, 3–5 high
CURB-65 is the British Thoracic Society’s bedside severity score for community-acquired pneumonia, chosen for its simplicity over the more accurate but 20-variable Pneumonia Severity Index. Each of five items scores one point. Mortality climbs from under 1% at 0 to nearly 30% at 4–5, which maps onto site-of-care decisions: patients scoring 0–1 can usually be treated at home with oral antibiotics, 2 warrants hospital assessment, and 3 or more needs admission with consideration of intensive care. CRB-65 drops the urea so general practitioners can apply it without blood tests. The score should complement, not replace, judgement about oxygenation, comorbidity and social support — hypoxia is not in the score and is a reason to admit regardless.
Worked example
A 72-year-old with respiratory rate 32, urea 8.2, blood pressure 110/58 and no confusion: urea 1 + RR 1 + diastolic ≤ 60 1 + age 1 = 4 — high severity, about 28% mortality, admit and consider ICU.
Frequently asked questions
How do I convert BUN to urea?
Urea (mmol/L) = BUN (mg/dL) × 0.357. The urea threshold of 7 mmol/L corresponds to BUN about 19–20 mg/dL.
CURB-65 or PSI?
PSI is better at identifying low-risk patients for discharge; CURB-65 is quicker and better at flagging severe disease. Many units use CURB-65 in the ED and PSI for research.
Related calculators
Clinical decision tool for education and for use by trained clinicians alongside judgement — not a diagnosis and not a substitute for medical assessment. Scores validated in specific populations may not apply to every patient.