CHA₂DS₂-VASc Score Calculator (atrial fibrillation stroke risk)

Understanding the CHA₂DS₂-VASc score calculator — concept and principle

The CHA₂DS₂-VASc score estimates the risk of stroke and systemic embolism in people with atrial fibrillation (AF) that is not caused by a mechanical heart valve or moderate-to-severe mitral stenosis. Clinicians weigh it with bleeding risk and patient preference when deciding on oral anticoagulation. This calculator also shows CHA₂DS₂-VA, the sex-neutral version adopted by the 2024 European Society of Cardiology (ESC) AF guideline.

How it is calculated

Add the points for each factor present:

• C congestive heart failure: 1
• H hypertension: 1
• A₂ age 75 or over: 2
• D diabetes mellitus: 1
• S₂ prior stroke, transient ischaemic attack (TIA) or thromboembolism: 2
• V vascular disease (prior myocardial infarction, peripheral artery disease, aortic plaque): 1
• A age 65–74: 1
• Sc sex category, female: 1

CHA₂DS₂-VASc ranges from 0 to 9. CHA₂DS₂-VA is the same total without the sex point, so it ranges from 0 to 8.

The principle

Each factor was linked in cohort studies to more AF-related strokes; prior stroke and age 75 or over have the strongest effect, so they count double. In 2010 Lip and colleagues added vascular disease, age 65–74 and female sex to the older CHADS₂ score to identify truly low-risk patients more reliably. Female sex was later shown to act mainly as a risk modifier when other factors are present, so the 2024 ESC guideline removed it.

Worked example

1. Defaults: no heart failure, no hypertension, age under 65, no diabetes, no prior stroke or TIA, no vascular disease, not female.
2. CHA₂DS₂-VASc = 0 + 0 + 0 + 0 + 0 + 0 + 0 = 0.
3. CHA₂DS₂-VA = 0 − 0 = 0.
4. Guideline context: low risk — anticoagulation not usually recommended.
5. For comparison, a 70-year-old woman with hypertension scores 1 + 1 + 1 = 3 on CHA₂DS₂-VASc and 2 on CHA₂DS₂-VA.

How to read the result

Under the 2024 ESC guideline, using CHA₂DS₂-VA: a score of 2 or more means oral anticoagulation is recommended for most patients; a score of 1 means it should be considered; 0 means it is not usually recommended. Risk rises steadily with each point. Reassess it as age and diagnoses change.

Common mistakes

• Counting age twice: 65–74 earns 1 point and 75 or over earns 2, never both.
• Using the score for AF with a mechanical valve or moderate-to-severe mitral stenosis, where anticoagulation is decided differently.

Frequently asked questions

Why did the 2024 ESC guideline drop the female sex point?

Female sex raises risk mainly in combination with other factors, and removing it makes the thresholds simpler and identical for men and women.

Does a score of 0 mean no stroke risk?

No. It means the risk is low enough that the expected benefit of anticoagulation usually does not outweigh bleeding risk.

Sources: Lip G. Y. H. et al., Chest, 2010 (derivation of CHA₂DS₂-VASc) · Van Gelder I. C. et al., 2024 ESC Guidelines for the management of atrial fibrillation, European Heart Journal, 2024