CURB-65 Score Calculator

How it is calculated

Five inputs, each entered as 1 (criterion present) or 0 (absent): confusion, raised urea, respiratory rate, low blood pressure and age. The score is simply the sum, score = C + U + R + B + 65, so it ranges from 0 to 5. The tool turns it into a band: 0 or 1 is shown as low risk, 2 as moderate risk, and 3, 4 or 5 as high risk (severe). Any value other than 0 or 1, such as 2, or a missing field, returns no result. The tool does not measure anything itself: you decide whether each criterion is met, using the thresholds from the published CURB-65 rule (for example age 65 or older). It is a decision aid for clinicians and students and does not replace clinical judgment or tell anyone what treatment to give.

Common mistakes

• Entering the measured value instead of 0 or 1. Typing the respiratory rate of 32 returns nothing; you enter 1 once the rate meets the threshold.
• Counting pre-existing confusion. The criterion is new confusion, not a long-standing condition such as dementia.
• Mixing up urea units. The rule is stated for blood urea in mmol/L (BUN in mg/dL gives a different number), so convert before deciding on 0 or 1.
• Leaving a field blank when unsure. A blank field gives no score at all, so each of the five needs an explicit 0 or 1.
• Reading the band as a decision about admission. The score is one input among others, including oxygen levels, other illnesses and social circumstances.