30-day mortality in community-acquired pneumonia. Free to use.
CURB-65 (CURB-65 Pneumonia Severity Score) is a validated clinical instrument used to assess 30-day mortality in community-acquired pneumonia. The instrument contains 5 items.
Source / attribution: Lim WS et al., Thorax 2003
Like all screening or assessment instruments, CURB-65 is a structured aid — not a diagnostic test in isolation. Results should be interpreted alongside history, examination, and clinical context. Where a score crosses an actionable threshold, the next step is typically a more detailed clinical evaluation rather than a definitive diagnosis.
Answer all 5 items below to see your CURB-65 score and interpretation.
All scoring runs in your browser. No data is sent anywhere — close the tab and the answers are gone.
CURB-65 uses weighted summation: each item carries a fixed weight that is added when the response indicates a positive finding.
Scoring notes: Educational use only.
The cutoffs below are drawn from the published validation literature. Always interpret in clinical context.
| Score range | Band | Interpretation |
|---|---|---|
| 0–1 | Low risk | Treat at home. |
| 2–2 | Moderate risk | Brief admission or close follow-up. |
| 3–5 | Severe | Severe — admit; ICU at 4 or 5. |
This is an illustrative walkthrough, not a real patient. Follow the same four steps with your own answers — or use the live calculator at the top of this page.
Mark each item Yes or No. Each "Yes" adds the item's weight; each "No" adds 0. The example below uses illustrative answers.
| # | Item | Example response | Score |
|---|---|---|---|
| 1 | Confusion (new disorientation) | No | 0 |
| 2 | BUN > 19 mg/dL (urea > 7 mmol/L) | Yes | 1 |
| 3 | RR ≥ 30/min | No | 0 |
| 4 | SBP < 90 mmHg or DBP ≤ 60 mmHg | Yes | 1 |
| 5 | Age ≥ 65 | No | 0 |
Add the weights from the items where you marked "Yes" (skip the "No" answers — they contribute 0).
0 + 1 + 0 + 1 + 0 = 2
Find the row in the interpretation table whose range contains your total:
Total = 2 falls between 2 and 2 → Moderate risk
Moderate risk. Consider short hospital stay or close outpatient supervision.
A score is one input alongside history and examination. CURB-65 supports clinical judgment — it does not replace it.
If CURB-65 doesn't fit your context, related instruments in pulmonology include:
| Scale | Measures | Items | Time |
|---|---|---|---|
| mMRC Dyspnea Scale | Functional impact of breathlessness | 1 | — |
| PERC Rule | Rule out PE in low-risk patients | 8 | — |
| sPESI | 30-day mortality risk after acute PE | 6 | — |
| Wells Score (PE) | Pre-test probability of pulmonary embolism | 7 | — |
| APGAR Score | Rapid assessment of newborn at 1 and 5 min | 5 | — |
| ASA Physical Status | Pre-operative health status | 1 | — |
| CHA2DS2-VASc | Annual stroke risk in non-valvular atrial fibrillation | 8 | — |
| Glasgow Coma Scale | Level of consciousness after head injury | 3 | — |
CURB-65 (CURB-65 Pneumonia Severity Score) is a validated instrument that assesses 30-day mortality in community-acquired pneumonia. It is designed for clinicians, medical students, evidence-synthesis researchers. The 5 items are combined to produce a total score.
CURB-65 contains 5 items. Item scores are combined with weighted scoring to produce the total. Scores run from 0 to 5, grouped into 3 interpretation bands from ‘Low risk’ up to ‘Severe’.
On the CURB-65 (total score 0–5), scores of 3–5 fall in the ‘Severe’ band — interpreted as: Severe — admit; ICU at 4 or 5. The full ladder is: 0–1 — Low risk: Treat at home.; 2 — Moderate risk: Brief admission or close follow-up.; 3–5 — Severe: Severe — admit; ICU at 4 or 5. A higher score reflects a more severe presentation, and crossing a cutoff is a prompt to step up assessment or care — but these bands are screening thresholds, not diagnoses.
Scores of 0–1 fall in the ‘Low risk’ band: Treat at home. A low score is reassuring but does not by itself rule out the underlying condition — if symptoms or clinical suspicion persist, reassess over time or use a complementary evaluation rather than relying on the number alone.
Yes — CURB-65 is in the public domain and free for clinical, educational, and research use without permission. You can use this calculator and the scale itself freely; if you publish results or reproduce the scale, cite the original source paper.
Lim WS et al. Thorax. 2003;58(5):377-382. This is the original publication for the CURB-65 — the reference to cite when reporting results.
No. CURB-65 is a structured assessment aid, not a diagnostic test. Its proper role is clinical assessment of 30-day mortality in community-acquired pneumonia — it standardizes assessment and flags who needs closer evaluation, but the result must be weighed alongside history, examination, and clinical context. When a score conflicts with your clinical impression, clinical judgment takes precedence; treatment decisions should never rest on a screening score alone.
CURB-65 is supported by the following peer-reviewed sources: