CHA2DS2-VASc Stroke Risk Calculator
Use this tool for non-valvular atrial fibrillation stroke risk stratification. Select all applicable factors and click calculate.
What is the CHA2DS2-VASc score?
The CHA2DS2-VASc score is a clinical tool used to estimate annual stroke risk in people with atrial fibrillation (AF), especially non-valvular AF. It helps clinicians decide when oral anticoagulation should be considered to reduce embolic stroke risk.
The name comes from each risk component: Congestive heart failure, Hypertension, Age, Diabetes, Stroke history, Vascular disease, Age (second tier), and Sc sex category.
Point breakdown used in this calculator
| Risk Factor | Points |
|---|---|
| Congestive heart failure / LV dysfunction | 1 |
| Hypertension | 1 |
| Age 75 years or older | 2 |
| Diabetes mellitus | 1 |
| Prior stroke, TIA, or systemic embolism | 2 |
| Vascular disease (MI, PAD, aortic plaque) | 1 |
| Age 65-74 years | 1 |
| Sex category: female | 1 |
How to interpret the result
General approach
In practice, higher scores correspond to higher annual stroke risk. Most guidelines suggest no anticoagulation for very low-risk patients and stronger consideration as scores rise. The final decision should include bleeding risk, kidney/liver function, medications, frailty, and patient goals.
- Low risk: usually no anticoagulation recommended.
- Intermediate risk: anticoagulation may be considered.
- Higher risk: anticoagulation is often recommended unless contraindicated.
Sex category nuance
Female sex is included in CHA2DS2-VASc but often acts as a risk modifier rather than a stand-alone trigger for therapy. That is why many clinicians focus on both the total score and the non-sex portion of the score before making treatment recommendations.
When this tool is useful (and when it is not)
This calculator is most useful in adults with atrial fibrillation where stroke prevention planning is needed. It is not a substitute for specialist evaluation in complex cases, such as:
- Mechanical heart valves or moderate/severe mitral stenosis
- Recent major bleeding or severe thrombocytopenia
- Advanced liver disease, severe kidney impairment, or pregnancy
- Situations requiring shared decision-making about risk tolerance
Practical checklist before prescribing anticoagulation
A complete plan usually includes more than stroke score alone. A practical workflow often includes:
- Confirm AF diagnosis and pattern (paroxysmal, persistent, permanent).
- Calculate CHA2DS2-VASc and discuss absolute risk.
- Assess bleeding risk factors and modifiable contributors.
- Review renal function, liver function, and drug interactions.
- Use shared decision-making to select strategy and follow-up schedule.
Example patient scenarios
Example 1: lower risk profile
A 58-year-old male with AF and no other risk factors has a score of 0. This is generally considered low risk, and anticoagulation is often not indicated.
Example 2: intermediate profile
A 68-year-old male with hypertension has score 2 (age 65-74 + hypertension). This typically reaches a threshold where anticoagulation is often recommended, depending on bleeding risk and patient preference.
Example 3: higher risk profile
A 79-year-old female with diabetes and prior TIA has a high score. In this setting, stroke prevention with anticoagulation is generally strongly considered unless there is a major contraindication.
Bottom line
The CHA2DS2-VASc score is a fast, evidence-based way to frame stroke risk conversations in atrial fibrillation. Use it as a decision aid, not as a stand-alone diagnosis or treatment order. If you are a patient, discuss your score with your clinician and ask how it changes your personal treatment options.