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Free Charlson Comorbidity Index Calculator (2026)
The Charlson Comorbidity Index (CCI) calculator scores a patient’s overall burden of chronic disease from 19 weighted conditions, each worth 1, 2, 3, or 6 points depending on how strongly it predicts mortality, and sums them into a single number. Originally developed to adjust for comorbidity when following patients over time in longitudinal studies, it is used today mainly in research, registry analysis, and outcomes work — especially oncology — to risk-adjust survival comparisons across patient groups with different baseline health. It is built for researchers, epidemiologists, oncologists, and hospitalists doing chart review, cohort description, or prognostic assessment, not for bedside acute-severity triage: it captures chronic comorbidity burden, not how physiologically unstable a patient is right now. Check every condition a patient has ever been diagnosed with from the list below; the calculator sums the points and reports the raw score plus a qualitative comorbidity-burden band.
Clinical decision-support aid, not a substitute for clinical judgment. These tools implement published scoring criteria for education and workflow support. They are not a medical device and have not been reviewed by the FDA or any regulatory body. Every result should be interpreted by a qualified clinician in the context of the full clinical picture, not used as a standalone diagnostic or treatment decision.
Comorbidity burden
Charlson Index
Check every applicable condition below, grouped by point value. The calculator sums the points as you go — toggle a box and recalculate to update the score.
2 points each
3 points
6 points each
Charlson ME, et al. J Chronic Dis. 1987;40(5):373–383 (original) · Quan H, et al. Med Care. 2005;43(11):1130–1139 (ICD-10 coding algorithms) · Charlson M, et al. J Clin Epidemiol. 1994;47(11):1245–1251 (age-adjusted variant).
Worked example
Consider a patient with a documented prior myocardial infarction (1 point), congestive heart failure (1 point), and diabetes with end-organ damage such as retinopathy, nephropathy, or neuropathy (2 points). Summing the three gives a Charlson Comorbidity Index of 4 — checking the same three boxes in the calculator above reproduces the same total, and is in fact how the calculator loads by default.
A score in this range is generally described as a moderate comorbidity burden: enough chronic disease to matter for prognosis and treatment planning, but well short of the highest-scoring categories, like metastatic cancer or AIDS, each worth 6 points on their own.
Methods, assumptions & limitations
Methods sentence. Comorbidity burden was quantified using the (unweighted) Charlson Comorbidity Index, the sum of 19 predefined condition categories weighted 1–6 points each based on their association with 1-year mortality in the original derivation cohort (Charlson et al., 1987), with conditions optionally ascertained from administrative data using the ICD-10 coding algorithm described by Quan et al. (2005).
On mortality claims. Higher Charlson scores correlate with substantially increased 1-year and 10-year mortality in the original derivation cohort and in numerous subsequent validation studies, across a wide range of clinical and research settings. This calculator deliberately reports the raw comorbidity score only, not a specific survival percentage: that conversion is cohort- and context-dependent, and stating one number here would overstate the precision of what is, at bottom, a comorbidity count.
Age-adjusted variant. An age-adjusted version of the index also exists, adding one point per decade of age over 40, and is widely used in oncology and outcomes research to combine comorbidity and age into a single prognostic index (Charlson et al., 1994). This calculator implements only the original 19-item score shown above, without the age adjustment.
When not to use this calculator. The Charlson Index is a baseline comorbidity-burden index for research and prognosis, not an acute severity score — it does not capture current physiologic derangement. When the question is how unstable a patient is right now rather than their underlying chronic disease burden, an acute score such as qSOFA, CURB-65, or APACHE is more appropriate.
Common questions
What counts as a “point” in the Charlson Comorbidity Index?
Each of the 19 conditions is weighted by how strongly it was associated with 1-year mortality in the original 1987 derivation cohort. Conditions like prior myocardial infarction, congestive heart failure, and uncomplicated diabetes are worth 1 point each; more severe conditions such as hemiplegia, moderate-to-severe renal disease, and diabetes with end-organ damage are worth 2 points; moderate-to-severe liver disease is worth 3 points; and the two most heavily weighted categories, metastatic solid tumor and AIDS, are worth 6 points each. The final score is simply the sum of every applicable condition’s points, with no cap and no interaction between categories.
Does a higher Charlson score mean a patient will die sooner?
A higher score is consistently associated with higher mortality risk across the original derivation cohort and a large body of subsequent validation research, in both hospital and outpatient settings. It is not, however, a precise individual prediction of survival time or probability — the exact relationship between a given score and outcome varies by population, disease context, and follow-up period, which is why this calculator reports only the raw score and a qualitative comorbidity-burden band rather than a specific percentage. For an individual patient, the score is best used as one input into a broader prognostic conversation, not as a standalone survival estimate.
Is there an age-adjusted version of the Charlson Index?
Yes. The age-adjusted Charlson Comorbidity Index adds one point for each decade of a patient’s age over 40 — for example, +1 at ages 50–59, +2 at 60–69, and so on — combining comorbidity burden and age into a single prognostic index. It is widely used in oncology and outcomes research, where age itself is an independent prognostic factor alongside comorbidity. This calculator implements only the original, non-age-adjusted 19-item score described in the references below; if a study protocol or journal specifically calls for the age-adjusted version, add the age points by hand using the rule above.
Primary references
- Charlson ME, Pompei P, Ales KL, MacKenzie CR. A new method of classifying prognostic comorbidity in longitudinal studies: development and validation. J Chronic Dis. 1987;40(5):373–383.
- Quan H, Sundararajan V, Halfon P, et al. Coding algorithms for defining comorbidities in ICD-9-CM and ICD-10 administrative data. Med Care. 2005;43(11):1130–1139.
- Charlson M, Szatrowski TP, Peterson J, Gold J. Validation of a combined comorbidity index. J Clin Epidemiol. 1994;47(11):1245–1251.
Related research support
Using the Charlson Index in a cancer-outcomes or registry study?
The Charlson Comorbidity Index is one of the most widely used comorbidity-adjustment tools in cancer-outcomes and survival research built on registries like SEER. If that’s the kind of analysis behind your project, Editverse’s SEER Cancer Outcomes Study service handles the registry-linked survival analysis and manuscript-ready methods and results end to end.