Calculate the CURB-65 score to estimate pneumonia severity and 30-day mortality risk from confusion, urea/BUN, respiratory rate, blood pressure, and age.
📖 CURB-65 Score (Lim et al., 2003)Fill in the fields on the left with your information, then press Calculate to see your result instantly. No sign-up required, and no data is sent anywhere — everything is calculated right in your browser.
CURB-65 is a widely used clinical scoring tool that estimates the severity of community-acquired pneumonia and the likelihood of a poor outcome within 30 days. It assigns one point each for five criteria — new Confusion, an elevated blood Urea/BUN level, a Respiratory rate of 30 breaths per minute or more, low Blood pressure, and Age 65 or older — giving the tool its name (CURB-65). The five points are added for a total score from 0 to 5, which maps to three broad risk categories: low, moderate, and high, each associated with a different typical management setting, from outpatient treatment at the low end to hospital admission with possible intensive care consideration at the high end. This calculator only totals the points from the values you enter; it doesn't replace the judgment of the clinical team managing the patient, who will also weigh other factors like oxygen saturation, existing health conditions, and how the patient looks in person.
Deciding whether a patient with pneumonia can safely go home or needs to be admitted to hospital — and how urgently — is one of the more consequential judgment calls in everyday clinical practice. Community-acquired pneumonia ranges enormously in severity, from a case that clears with a short course of oral antibiotics at home to a life-threatening illness requiring intensive care, and making that call quickly and consistently across different clinicians and different patients is exactly the kind of problem a standardized scoring system is designed to solve.
CURB-65 was developed by Lim and colleagues and published in 2003 in the medical journal Thorax, refining earlier severity criteria from the British Thoracic Society into a leaner, five-item tool that could be calculated quickly at the bedside using information already gathered during a standard clinical assessment: mental status, a basic blood test, vital signs, and the patient's age. Its simplicity is part of why it has been adopted so widely — unlike more elaborate severity scores that require dozens of variables, CURB-65 can be calculated in under a minute with information a clinician typically already has in hand.
Each of the five criteria was chosen because it independently correlates with a worse pneumonia outcome: confusion often signals reduced brain perfusion or early sepsis; an elevated urea/BUN reflects kidney stress, often from dehydration or reduced blood flow; a fast respiratory rate signals the body working harder to compensate for impaired lung function; low blood pressure signals the circulatory system struggling to maintain adequate perfusion; and advanced age is consistently associated with reduced physiological reserve and higher mortality across many acute illnesses, pneumonia included. None of these five signs is unique to pneumonia, but together they capture a meaningful cross-section of how sick a patient's body is at that specific moment.
Since its original publication, CURB-65 has been validated in numerous subsequent studies across different countries and healthcare settings, and it now appears in pneumonia management guidelines from professional societies worldwide. It isn't perfect — no five-variable score could be — and it's generally used alongside clinical judgment, oxygen saturation readings, chest imaging findings, and a look at the whole patient, rather than as a mechanical stand-alone rule. But as a fast, reproducible starting point for triaging pneumonia severity, it remains one of the most enduring and widely taught tools in acute medicine, more than two decades after it was first described.
CURB-65 is a widely used clinical tool that estimates the severity of community-acquired pneumonia and the associated 30-day mortality risk, based on five criteria: Confusion, Urea (BUN), Respiratory rate, Blood pressure, and age 65 or older.
One point is given for each of the following present: new confusion; blood urea nitrogen above 19 mg/dL (urea above 7 mmol/L); respiratory rate of 30 breaths per minute or more; systolic blood pressure under 90 mmHg or diastolic blood pressure of 60 mmHg or less; and age 65 or older. The five points are added for a total score from 0 to 5.
A score of 0-1 suggests low risk, often suitable for outpatient (home) treatment. A score of 2 suggests moderate risk, where hospital admission or closely supervised outpatient care is often considered. A score of 3-5 suggests high risk, generally warranting hospital admission, with scores of 4-5 often prompting consideration of intensive care.
It was developed by Lim and colleagues and published in 2003 in the journal Thorax, building on earlier British Thoracic Society pneumonia severity criteria, and has since been validated in numerous studies and widely adopted by clinical guidelines worldwide.
No. This tool only totals the CURB-65 points from the values you enter. It doesn't diagnose pneumonia, order tests, or make a treatment decision — those require an in-person clinical assessment, chest imaging, and judgment from a qualified physician, who will also weigh factors CURB-65 doesn't capture, like oxygen levels and other health conditions.