What is the CHA₂DS₂-VASc score?

It is a clinical prediction rule used to estimate stroke risk in patients with atrial fibrillation. Each letter represents a risk factor: Congestive heart failure, Hypertension, Age ≥75 (doubled), Diabetes, Stroke/TIA (doubled), Vascular disease, Age 65–74, and Sex category (female). Scores range from 0 to 9.

When should anticoagulation be started?

Guidelines generally recommend anticoagulation for men with a score ≥ 1 and women with a score ≥ 2. A score of 0 in men or 1 in women (where the only point is sex) is considered low risk and may not require anticoagulation. Always consult current guidelines and clinical judgment.

How is CHA₂DS₂-VASc different from CHADS₂?

CHA₂DS₂-VASc is an expanded version of the older CHADS₂ score. It adds vascular disease, age 65–74, and female sex as additional risk factors. It is better at identifying truly low-risk patients who may not need anticoagulation.

Why is female sex a risk factor?

Female sex is included as a risk modifier because studies show women with atrial fibrillation have a higher relative stroke risk than men, particularly at older ages. However, female sex alone (score of 1) is generally not considered an indication for anticoagulation in the absence of other risk factors.

Online Medical Tools — CHA₂DS₂-VASc Score

Printed on 2/13/2026

For informational purposes only. This is not medical advice.

Cardiology

CHA₂DS₂-VASc Score

The CHA₂DS₂-VASc score is the most widely used clinical prediction tool for estimating stroke risk in patients with non-valvular atrial fibrillation. It helps clinicians decide whether anticoagulation therapy is warranted by scoring risk factors including heart failure, hypertension, age, diabetes, prior stroke, vascular disease, and sex.

Compare with HAS-BLED Score

Formula: Score = CHF(1) + Hypertension(1) + Age≥75(2) + Diabetes(1) + Stroke(2) + Vascular(1) + Age 65–74(1) + Female(1)

How to Interpret Your Result

Your CHA₂DS₂-VASc score ranges from 0 to 9 and directly corresponds to an annual stroke risk. A score of 0 in men (or 1 in women where the only point is for female sex) indicates low risk — annual stroke rate is approximately 0.2–0.3%, and anticoagulation is generally not recommended. A score of 1 in men or 2 in women places you in a moderate-risk category where anticoagulation should be considered. A score of 2 or higher in men (3+ in women) carries a clearly elevated stroke risk (roughly 2–15% per year depending on the score) and anticoagulation is generally recommended. The score should always be interpreted alongside the HAS-BLED bleeding risk score to weigh the benefit of stroke prevention against the risk of major bleeding from anticoagulation therapy.

When to Use This Tool

Use this calculator whenever assessing the need for anticoagulation in a patient with non-valvular atrial fibrillation or atrial flutter. It is the standard risk stratification tool recommended by the ESC, AHA/ACC, and most international cardiology guidelines. It is particularly useful at the time of a new atrial fibrillation diagnosis, during follow-up visits when risk factors may have changed (e.g., new diagnosis of diabetes or vascular disease), and when re-evaluating anticoagulation decisions in patients whose clinical status has evolved.

Limitations

The CHA₂DS₂-VASc score was designed for non-valvular atrial fibrillation. Patients with valvular AF (especially mitral stenosis or mechanical heart valves) require anticoagulation regardless of their score and should not rely on this tool for decision-making. The score treats all risk factors as binary (present or absent) and does not weight severity. For example, well-controlled hypertension and refractory hypertension receive the same point. Similarly, a remote TIA and a recent disabling stroke both score 2 points. Female sex alone (score of 1) is considered a risk modifier rather than an independent risk factor — guidelines do not recommend anticoagulation for women whose only point is sex category. The score also does not account for certain emerging risk factors such as chronic kidney disease, obesity, or obstructive sleep apnea, which may independently increase stroke risk in atrial fibrillation.

Disclaimer: This tool is for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with questions about your health.