CHA2DS2-VASc Stroke Risk Calculator
Use this tool to estimate annual stroke risk in patients with atrial fibrillation (AF). Enter age, sex, and clinical risk factors below.
Educational use only. This calculator does not replace clinician judgment, guideline-based care, or shared decision-making.
What is the CHA2DS2-VASc score?
The CHA2DS2-VASc score is a validated risk stratification tool used in atrial fibrillation to estimate the risk of ischemic stroke. It helps clinicians decide whether oral anticoagulation should be discussed or recommended.
In AF, blood flow in the atria can become turbulent, increasing the chance of clot formation. If a clot embolizes to the brain, it can cause stroke. The score captures common clinical factors linked to this risk.
How points are assigned
- Congestive heart failure / LV dysfunction: 1 point
- Hypertension: 1 point
- A2 Age 75 years or older: 2 points
- Diabetes mellitus: 1 point
- S2 Prior stroke, TIA, or systemic embolism: 2 points
- Vascular disease (prior MI, PAD, aortic plaque): 1 point
- A Age 65 to 74 years: 1 point
- Sc Sex category (female): 1 point
Maximum score is 9. Age is counted once (either +1 for 65–74 or +2 for 75+).
Estimated annual stroke risk by score
| CHA2DS2-VASc Score | Approximate Annual Stroke Risk |
|---|---|
| 0 | 0.0% |
| 1 | 1.3% |
| 2 | 2.2% |
| 3 | 3.2% |
| 4 | 4.0% |
| 5 | 6.7% |
| 6 | 9.8% |
| 7 | 9.6% |
| 8 | 6.7% |
| 9 | 15.2% |
How to interpret results
General approach
A practical interpretation is based on non-sex risk points:
- 0 non-sex points: Low risk (anticoagulation usually not indicated).
- 1 non-sex point: Intermediate risk (consider anticoagulation depending on bleeding risk and patient preference).
- 2+ non-sex points: Higher risk (anticoagulation is generally recommended if no contraindication).
Remember bleeding risk too
Stroke prevention must be balanced against bleeding risk. Tools like HAS-BLED can support that discussion, but they should guide monitoring and risk reduction—not be used alone to deny treatment when stroke risk is high.
Clinical caveats and limitations
- This score estimates population-level risk; individual risk can vary.
- Risk percentages differ across cohorts and guideline eras.
- Sex category should be interpreted in clinical context, especially when it is the only point.
- Management depends on renal function, frailty, prior bleeding, drug interactions, and patient goals.
FAQ
Can this calculator diagnose atrial fibrillation?
No. It is only a stroke-risk tool after AF (or atrial flutter) is already established.
Should aspirin be used instead of anticoagulation?
In most AF stroke-prevention settings, aspirin is much less effective than anticoagulation. Current guidelines generally favor oral anticoagulants when indicated.
Is a higher score always an emergency?
Not necessarily an emergency, but it signals increased risk and the need for timely review with a qualified clinician.