CURB-65 Calculator
Score community-acquired pneumonia severity with CURB-65 or the bedside-only CRB-65. Enter raw vitals (age, urea or BUN, respiratory rate, blood pressure) and let the tool award the points, or switch to quick toggles. You get the 0 to 5 score, matching 30-day mortality, a risk band, a suggested care setting, and a breakdown of which criteria were met.
Formula
Worked example
An 80-year-old (1) who is confused (1) with a respiratory rate of 32 (1), BUN 24 mg/dL (1), and BP 130/75 (0) scores 4 of 5: high risk, roughly 28% 30-day mortality, admit and assess for ICU. Dropping the urea point gives a CRB-65 of 3, also high risk.
What the CURB-65 score measures
CURB-65 is a validated severity tool for community-acquired pneumonia in adults. It awards one point each for five findings, Confusion, raised Urea, a high Respiratory rate, low Blood pressure, and age 65 or older, for a total of 0 to 5. The score correlates with 30-day mortality and is used to help decide whether a patient can be treated at home, needs a hospital bed, or may require intensive care. It is deliberately simple so it can be applied quickly at the bedside or in the emergency department.
Two input modes: raw vitals or quick toggles
This calculator can score from raw clinical values or from simple toggles. In raw-vitals mode you enter the age, the urea or BUN reading, the respiratory rate, and both systolic and diastolic blood pressure, and the tool applies each threshold for you: age 65 or older, BUN above 19 mg/dL (urea above 7 mmol/L), rate of 30 or more, and systolic below 90 or diastolic of 60 or lower. The urea field accepts either US units (BUN in mg/dL) or SI units (serum urea in mmol/L) and converts internally. Toggle mode is faster when you have already assessed each criterion and just want to add up the points.
How each criterion is defined
Confusion means new disorientation, often gauged by an Abbreviated Mental Test score of 8 or less. Urea is positive when blood urea nitrogen exceeds 19 mg/dL (serum urea above 7 mmol/L). Respiratory rate scores a point at 30 breaths per minute or more. Blood pressure scores when systolic is below 90 mmHg or diastolic is 60 mmHg or lower. The final point is simply age 65 or older. The related bedside-only version, CRB-65, drops the urea test for settings without immediate blood results and produces a 0 to 4 score with its own mortality bands.
Reading the result
A score of 0 or 1 marks low risk, with mortality around 1 to 3 percent, and most such patients can be treated as outpatients. A score of 2 is intermediate and often prompts a short hospital stay or close supervision. Scores of 3 to 5 are high risk, with mortality rising steeply, and usually warrant admission with assessment for intensive care at 4 or 5. The breakdown lists exactly which criteria were met so you can see what is driving the score. CURB-65 guides but does not replace clinical judgement; oxygen levels, comorbidities, and the ability to cope at home all factor into the final decision.
CURB-65 score, risk band, and disposition
| Score | 30-day mortality | Risk band | Suggested care setting |
|---|---|---|---|
| 0 | 0.6% | Low | Outpatient |
| 1 | 2.7% | Low | Outpatient |
| 2 | 6.8% | Intermediate | Short stay or supervised outpatient |
| 3 | 14% | High | Inpatient admission |
| 4 | 27.8% | High | Inpatient; consider ICU |
| 5 | 27.8% | High | Inpatient; consider ICU |
Approximate 30-day mortality from the original Lim et al. (2003) cohort. Use alongside clinical judgement, not in place of it. CRB-65 uses the same criteria minus urea for a 0 to 4 score.
Frequently asked questions
What is the difference between CURB-65 and CRB-65?
CRB-65 uses the same criteria minus the urea blood test, giving a 0 to 4 score. It is designed for primary care or any setting where blood results are not immediately available, while CURB-65 is used when a urea or BUN value can be obtained. Switch between them with the score selector at the top of the calculator.
Can I enter raw blood pressure and urea values?
Yes. In raw-vitals mode you enter age, the urea or BUN reading (mg/dL or mmol/L), the respiratory rate, and both blood pressure numbers, and the calculator applies the clinical thresholds and awards the points automatically. Quick-toggle mode is available when you have already assessed each criterion.
What urea or BUN value scores a point?
The urea criterion scores one point when serum urea is above 7 mmol/L, which is equivalent to a blood urea nitrogen (BUN) above 19 mg/dL. Values at or below that threshold score zero. The calculator handles the unit conversion for you.
Can CURB-65 decide admission on its own?
No. CURB-65 is a guide, not a rule. It does not capture oxygen saturation, chronic illness, or social circumstances, so clinicians combine it with judgement and local guidelines. These results are estimates, and clinical decisions should be made by a qualified professional.