CURB-65 Score Calculator

🩺 CURB-65 Score Calculator

For Community-Acquired Pneumonia Severity

Reviewed by the DosePilot Medical Team · Last medically reviewed: June 2026

ConfusionNew onset (e.g., AMTS ≤ 8)
Urea > 7 mmol/Lor BUN > 19 mg/dL(Not used for CRB-65 score)
Respiratory Rate ≥ 30Breaths per minute
Blood Pressure (Low)Systolic < 90 mmHg or Diastolic ≤ 60 mmHg
Age ≥ 65Years old
Show score breakdown

Recent Updates

  • The 2019 ATS/IDSA community-acquired pneumonia guideline recommends using a validated severity score (CURB-65 or PSI) together with clinical judgment for the site-of-care decision — not the score alone.
  • Where it has been validated, that guideline expresses a preference for the Pneumonia Severity Index (PSI) over CURB-65 for the admission decision, given PSI’s larger evidence base; CURB-65 remains valued for its speed and simplicity.
  • 30-day mortality rises steeply with the score, supporting the usual banding: 0–1 often outpatient, 2 consider admission/observation, and 3–5 admit with assessment for intensive care.

Sources: Lim et al., Thorax 2003 (PMID 12728155) · Metlay et al., ATS/IDSA CAP guideline, Am J Respir Crit Care Med 2019 (PMID 31573350)

Key Knowledge Points

  • The CURB-65 calculator is a mnemonic used to assess the severity of community-acquired pneumonia (CAP) and predict 30-day mortality.
  • This tool guides disposition decisions: whether to treat a patient as an outpatient, admit to the hospital, or consider intensive care.
  • The CRB-65 score is a simplified version that omits the Urea lab value, making it ideal for primary care or outpatient settings.
  • The score is a guide, not a replacement for clinical judgment. Factors like oxygen saturation and comorbidities are also critical.

About This CURB-65 Calculator

This CURB-65 Calculator is an essential clinical tool for rapidly assessing the severity of community-acquired pneumonia (CAP). By stratifying patients based on mortality risk, this score helps guide crucial management decisions, such as determining the appropriate site of care. Our interactive version calculates both the full CURB-65 score (for hospital settings where labs are available) and the simplified CRB-65 score simultaneously, providing instant, color-coded results to support your clinical workflow.

Scoring System Explained

The CURB-65 Calculator assigns one point for each of the five prognostic criteria present at the time of evaluation. The CRB-65 score omits the Urea component.

  • C – Confusion (new disorientation, AMTS ≤ 8)
  • U – Urea > 7 mmol/L (or BUN > 19 mg/dL)
  • R – Respiratory Rate ≥ 30 breaths/min
  • B – Blood Pressure (Systolic < 90 mmHg or Diastolic ≤ 60 mmHg)
  • 65 – Age ≥ 65 years

Clinical Interpretation & Management

The calculated score correlates with 30-day mortality risk and provides a framework for deciding the site of care. Current ATS/IDSA guidance uses such scores as an adjunct to clinical judgment — alongside oxygenation, comorbidities, and social factors — rather than as the sole determinant, and prefers the Pneumonia Severity Index (PSI) where it has been validated.

CURB-65 Score

  • 0-1 (Low Risk): Mortality ~1.5%. Consider outpatient treatment.
  • 2 (Moderate Risk): Mortality 9.2%. Consider hospital admission.
  • 3-5 (High Risk): Mortality 22%. Urgent hospital admission, with ICU assessment for scores 4-5.

CRB-65 Score

  • 0 (Very Low Risk): Mortality <1%. Outpatient treatment is usually appropriate.
  • 1-2 (Increased Risk): Consider hospital admission.
  • ≥3 (High Risk): Urgent hospital admission required.

Frequently Asked Questions (FAQ)

1. What is the difference between CURB-65 and CRB-65?

CRB-65 is a simplified version of CURB-65 that does not require a blood test for Urea (BUN). This makes it more practical for use in primary care or community settings where lab results are not immediately available.

2. Should I always admit a patient with a CURB-65 score of 2?

A score of 2 places the patient in a moderate-risk group where hospital admission should be strongly considered. The final decision should be based on clinical judgment, considering factors like oxygen saturation, ability to take oral medication, and home support.

3. Is the CURB-65 Calculator better than the Pneumonia Severity Index (PSI)?

Both are validated tools. The CURB-65 is much simpler and faster to use. The PSI is more complex, with 20 variables, but may be slightly better at identifying low-risk patients who can be safely managed as outpatients. The choice often depends on institutional preference and clinical setting.

4. What does “AMTS ≤ 8” mean for the Confusion criterion?

The Abbreviated Mental Test Score (AMTS) is a 10-point questionnaire to assess cognitive impairment. A score of 8 or less, if new for the patient, indicates confusion and earns a point in the CURB-65 score.

5. Does this calculator apply to hospital-acquired pneumonia (HAP)?

No. The CURB-65 and CRB-65 scores were specifically developed and validated for community-acquired pneumonia (CAP). Hospital-acquired or ventilator-associated pneumonia involves different pathogens and patient populations, requiring different assessment tools.

Related Calculators

📖 Sources:

  1. Lim, W. S., van der Eerden, M. M., Laing, R., et al. (2003). Defining community acquired pneumonia severity on presentation to hospital: an international derivation and validation study. Thorax, 58(5), 377–382.
  2. National Institute for Health and Care Excellence (NICE). (2019). Pneumonia in adults: diagnosis and management (Clinical guideline CG191).
  3. Metlay, J. P., Waterer, G. W., Long, A. C., et al. (2019). Diagnosis and Treatment of Adults with Community-acquired Pneumonia. American Journal of Respiratory and Critical Care Medicine, 200(7), e45-e67.

⚠️ Disclaimer:

This tool is for informational and educational purposes only and is not a substitute for professional clinical judgment. All treatment decisions must be made by a qualified healthcare professional considering the individual patient’s full clinical context.

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