CURB-65 Pneumonia Severity Calculator
CURB-65 is a simple severity score for community-acquired pneumonia that helps guide whether a patient can be managed at home or needs hospital care. It awards one point each for Confusion, raised Urea, Respiratory rate of 30 or more, low Blood pressure, and age 65 or older, giving a total from 0 to 5. Higher scores correlate with higher mortality and a greater need for inpatient management. Check each criterion that is present and the calculator returns the total and severity band. This is an educational tool, not a diagnosis or a substitute for clinical judgment.
CURB-65 scoring
Score = C + U + R + B + (age 65 or older)
Each present criterion = 1 point; total 0 to 5
0 to 1 = low; 2 = moderate; 3 to 5 = high severity
The score sums the five binary criteria. It is designed for rapid bedside use to support decisions about the site and intensity of care.
CURB-65 severity bands
- Score 0 to 1: low severity, outpatient management often appropriate.
- Score 2: moderate severity, consider hospital care.
- Score 3 to 5: high severity, hospital or intensive assessment.
- Mortality risk rises steadily with the score.
- Always combined with clinical judgment and social factors.
CURB-65: frequently asked questions
What does CURB-65 stand for?
CURB-65 is an acronym for its five criteria: Confusion, Urea over 7 mmol/L (about 19 mg/dL BUN, or about 20 mg/dL urea nitrogen), Respiratory rate 30 or more per minute, Blood pressure (systolic under 90 or diastolic 60 or less), and age 65 or older. Each present criterion scores 1 point.
How is the CURB-65 score interpreted?
A total of 0 to 1 suggests low severity, often suitable for outpatient care; 2 suggests moderate severity and consideration of hospital care; and 3 to 5 suggests high severity, often warranting hospital or intensive assessment. Scores guide, but do not dictate, the site of care.
What urea threshold is used?
The classic criterion is serum urea above 7 mmol/L. In US units this corresponds to a blood urea nitrogen (BUN) above roughly 19 to 20 mg/dL. Select whether the urea criterion is met based on your local units.
Is CURB-65 the only pneumonia severity tool?
No. The Pneumonia Severity Index (PSI) is another validated tool. CURB-65 is valued for its simplicity. Both support, rather than replace, clinical judgment about admission.
Is this a diagnosis?
No. CURB-65 is a severity score used by clinicians for community-acquired pneumonia. This calculator is educational and does not replace clinical assessment.
Official sources
- Centers for Disease Control and Prevention: Pneumonia information.
- National Library of Medicine (NCBI): CURB-65 validation literature.
Reviewed by the CalculatorHub team, edited by James Graham, 17 June 2026. See our methodology.