CURB-65 Score Calculator

Enter patient details — Confusion, Urea level, Respiratory Rate, Blood Pressure, and Age — to calculate the CURB-65 Score for community-acquired pneumonia (CAP) severity. You get a score from 0–5, a risk class, 30-day mortality estimate, and a recommended treatment setting.

Disclaimer: This tool is for informational and educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making any health-related decisions.

Confusion (new onset disorientation to person, place, or time) *

New mental confusion, not baseline dementia

Blood Urea Nitrogen (BUN) > 19 mg/dL (7 mmol/L) *

BUN > 19 mg/dL or urea > 7 mmol/L

Respiratory Rate ≥ 30 breaths/min *

Respiratory rate of 30 or more breaths per minute

Low Blood Pressure (SBP < 90 mmHg or DBP ≤ 60 mmHg) *

Systolic BP < 90 or diastolic BP ≤ 60 mmHg

Age ≥ 65 years *

Patient is 65 years of age or older

Results

CURB-65 Score

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Risk Class

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Estimated 30-Day Mortality

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Recommended Management

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Results Table

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Frequently Asked Questions

What does the CURB-65 score stand for?

CURB-65 is an acronym: C = Confusion (new onset), U = Urea > 19 mg/dL, R = Respiratory rate ≥ 30/min, B = low Blood pressure (SBP < 90 or DBP ≤ 60 mmHg), and 65 = Age ≥ 65 years. Each criterion scores 1 point, giving a maximum score of 5.

How is the CURB-65 score interpreted?

A score of 0–1 indicates low severity with outpatient treatment appropriate. Score 2 indicates moderate severity, often managed with short inpatient stay or supervised outpatient care. Scores of 3–5 indicate high severity, warranting hospital admission — with scores 4–5 suggesting consideration of ICU-level care.

What is the 30-day mortality risk for each CURB-65 score?

Approximate 30-day mortality rates are: Score 0 = ~0.6%, Score 1 = ~3.2%, Score 2 = ~13%, Score 3 = ~17%, Score 4 = ~41.5%, Score 5 = ~57%. These are derived from the original Lim et al. (2003) validation study.

Is CURB-65 used for all types of pneumonia?

CURB-65 is specifically validated for community-acquired pneumonia (CAP) — pneumonia acquired outside of a hospital setting. It is not validated for hospital-acquired pneumonia (HAP) or ventilator-associated pneumonia (VAP).

What is the difference between CURB-65 and PSI (Pneumonia Severity Index)?

Both tools assess CAP severity, but they differ in complexity. CURB-65 uses just 5 binary criteria and is quick to calculate at the bedside. The PSI (PORT score) incorporates 20 variables including lab values and comorbidities, making it more detailed but time-consuming. CURB-65 is preferred for rapid clinical triage.

Can CURB-65 be used without the blood urea nitrogen (BUN) result?

Yes — a simplified version called CRB-65 omits the urea criterion and can be used in outpatient or resource-limited settings where lab values aren't immediately available. CRB-65 uses only Confusion, Respiratory rate, Blood pressure, and Age ≥ 65, giving a maximum score of 4.

Does a low CURB-65 score rule out serious pneumonia?

A low CURB-65 score (0–1) suggests low 30-day mortality risk and often supports outpatient management, but it does not definitively rule out serious illness. Clinical judgment, comorbidities, oxygenation, social factors, and local protocols should always be considered alongside the score.

Who developed the CURB-65 score?

The CURB-65 score was developed by Lim et al. and published in Thorax in 2003, based on data from over 1,000 patients with community-acquired pneumonia across three countries. It was designed as a simpler alternative to the PSI for bedside use.