CHA₂DS₂-VASc Score Calculator
Estimate the yearly stroke risk of someone with non-valvular atrial fibrillation using the CHA₂DS₂-VASc score, and see what current guidelines recommend about anticoagulation. Each risk factor adds points — most add one, while age ≥75 and a prior stroke add two. Tick the factors that apply to get the score, the approximate annual stroke risk and the treatment category.
How the score adds up
C — CHF/LV dysfunction (1), H — hypertension (1), A₂ — age ≥75 (2), D — diabetes (1), S₂ — prior stroke/TIA/thromboembolism (2), V — vascular disease (1), A — age 65–74 (1), Sc — sex category, female (1). Maximum 9. Source: Lip GYH et al., Chest 2010; refined in successive ESC and ACC/AHA atrial-fibrillation guidelines.
Frequently asked questions
How is the CHA₂DS₂-VASc score calculated?
The CHA₂DS₂-VASc score adds one point each for congestive heart failure or LV dysfunction (C), hypertension (H), diabetes (D), vascular disease (V — prior MI, peripheral artery disease or aortic plaque), age 65–74 (A), and female sex (Sc); two points are added for age ≥75 (A₂) and for a prior stroke, TIA or thromboembolism (S₂). Age counts once — either two points at 75 and over, one point at 65–74, or none below 65. The total ranges from 0 to 9.
What score means I need blood thinners?
Guidelines base the recommendation on the score and sex. Oral anticoagulation is recommended at a score of 2 or more in men and 3 or more in women. It may be considered at 1 in men and 2 in women. It is not recommended at 0 in men or 1 in women, because female sex on its own does not raise risk enough to treat. The final decision weighs bleeding risk and patient preference.
Why does female sex add a point but not always change treatment?
Female sex is a “risk modifier” rather than an independent risk factor: it increases stroke risk only when at least one other risk factor is present. That is why a woman whose only point is for sex (score 1) is treated the same as a man with a score of 0, and the treatment thresholds are one point higher for women. That reasoning is also why the 2024 ESC guidelines dropped the sex category altogether, replacing this score with the sex-neutral CHA₂DS₂-VA score. Sex still modifies risk when other factors are present; it simply no longer shifts the anticoagulation threshold in the newer version.
How accurate is the annual stroke-risk percentage?
The percentages shown come from the original 2010 derivation cohort and are approximate. Different and larger cohorts report somewhat different rates, and the figures for the highest scores rest on small numbers of patients, so they are imprecise and not perfectly ordered. Use the score and the treatment category as the main output, and the percentage only as a rough guide.
When should the score not be used?
CHA₂DS₂-VASc is for non-valvular atrial fibrillation. It does not apply to valvular AF (moderate-to-severe mitral stenosis or a mechanical heart valve), where anticoagulation is indicated regardless of the score, and it does not by itself capture bleeding risk — clinicians pair it with a bleeding-risk tool such as HAS-BLED. This calculator is an educational reference, not medical advice.
This is a reference tool, not a diagnosis or medical advice. Results depend on the laboratory, assay and clinical context, and reference intervals vary between labs and by age and sex — always read your result against the range printed on your own report and discuss it with a qualified healthcare professional.
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