Calculate the CURB-65 score for community-acquired pneumonia severity assessment and see 30-day mortality plus published care-setting context.
The CURB-65 Pneumonia Severity Score Calculator is a validated severity worksheet for community-acquired pneumonia (CAP). Developed by Lim et al. (2003) from a study of more than 1,000 patients at 3 UK hospitals, CURB-65 uses five bedside variables to estimate 30-day mortality and provide care-setting context from the original cohorts.
The acronym CURB-65 stands for: Confusion (new-onset), Urea (BUN >19 mg/dL or >7 mmol/L), Respiratory rate (≥30/min), Blood pressure (SBP <90 or DBP ≤60), and age ≥65. Each criterion scores one point, yielding a total from 0 to 5. Lower scores generally track with lower short-term mortality, while higher scores are more often associated with inpatient or higher-acuity review.
This calculator auto-calculates criteria from entered vital signs and labs, provides both CURB-65 (with BUN) and CRB-65 (without lab work, for outpatient settings), and shows mortality data plus a criteria breakdown table. It is meant to support context, not replace bedside judgment.
Pneumonia severity is easy to underestimate when individual vital signs or labs are looked at in isolation. CURB-65 gives a compact way to summarize five major risk features and compare the resulting score with the original mortality data. That makes it useful as a worksheet for level-of-care conversations without turning the page into a stand-alone admit-or-discharge instruction.
CURB-65 Score (0–5): C = Confusion (new mental confusion) → 1 point U = Urea (BUN > 19 mg/dL / 7 mmol/L) → 1 point R = Respiratory rate ≥ 30/min → 1 point B = Blood pressure (SBP < 90 or DBP ≤ 60) → 1 point 65 = Age ≥ 65 years → 1 point 30-Day Mortality by Score: 0: 0.7%, 1: 2.1%, 2: 9.2%, 3: 14.5%, 4: 40%, 5: 57%
Result: CURB-65 Score: 5/5 — Very High Risk (57% 30-day mortality)
All 5 criteria are met: age 72 ≥ 65 (1), new confusion (1), BUN 25 > 19 (1), RR 32 ≥ 30 (1), SBP 85 < 90 (1). Score = 5 indicates 57% 30-day mortality in the original validation data. In published cohorts, that score sits in a high-acuity reference range rather than a lower-intensity outpatient context.
The original study by Lim et al. analyzed 1,068 patients from 3 UK hospitals and identified these 5 factors as independent predictors of 30-day mortality. The score was later validated in multiple international cohorts totaling more than 12,000 patients, confirming that it is a practical severity summary rather than just a theoretical mnemonic.
Score 0–1 is associated with low short-term mortality in the original data and often fits lower-acuity management discussions. Score 2 sits in an intermediate zone where inpatient review becomes more common. Scores 3–5 reflect progressively higher mortality and usually push the conversation toward higher-acuity monitoring. Those patterns are useful context, but the score does not issue an admit order by itself.
CURB-65 may underestimate severity in younger patients with severe sepsis (who score low on age), patients with hypoxemia but relatively preserved blood pressure, and immunocompromised patients. It does not account for imaging findings, lactate, oxygen requirement, or comorbidity burden. Always read the score alongside the bedside picture rather than in isolation.
Last updated:
This page assigns one point each for the five CURB-65 variables, then shows the total score beside the original mortality bands and a CRB-65 view when urea is unavailable. It is intended as a severity worksheet for community-acquired pneumonia so the bedside variables can be compared against the published score structure in one place.
The result is not a stand-alone admit-or-discharge rule. Oxygen requirement, frailty, inability to take oral therapy, multilobar disease, immunocompromise, and the wider bedside picture still matter beyond the score itself.
CURB-65 is a clinical prediction rule for community-acquired pneumonia severity, developed by Lim et al. in 2003. It uses 5 bedside parameters (Confusion, Urea, Respiratory rate, Blood pressure, age ≥65) to estimate 30-day mortality and add level-of-care context.
CURB-65 is most useful at initial assessment of an adult with community-acquired pneumonia. It helps frame how severe the presentation looks in the original cohorts, but it should sit alongside oxygenation, imaging, comorbidities, and bedside judgment rather than replacing them.
CRB-65 excludes the urea/BUN criterion, so it can be used without lab results. It scores 0–4 and is often used in outpatient or community settings as a quicker severity screen.
The Pneumonia Severity Index (PSI) uses 20 variables including lab values, comorbidities, and imaging. It may be more accurate for identifying low-risk patients but is more complex. CURB-65 is simpler and preferred for initial bedside assessment. Both are recommended by IDSA/ATS guidelines.
CURB-65 was validated for bacterial community-acquired pneumonia and may underestimate severity in COVID-19 pneumonia, which often features rapid respiratory deterioration despite initially stable vital signs. COVID-specific tools (such as 4C Mortality Score) should be preferred for SARS-CoV-2 infections.
Confusion refers to new-onset mental confusion, typically assessed using the Abbreviated Mental Test Score (AMTS ≤ 8) or any new disorientation to person, place, or time. Pre-existing cognitive impairment (e.g., dementia) should not be counted unless there is acute change from baseline.