Introduction
The CHA₂DS₂-VASc score helps doctors figure out how likely a person with atrial fibrillation (AFib) is to have a stroke. AFib is a common heart condition where the heart beats in an uneven rhythm. This irregular beat can cause blood clots to form, and those clots can travel to the brain and cause a stroke.
The CHA₂DS₂-VASc calculator looks at simple risk factors like age, sex, high blood pressure, diabetes, heart failure, past strokes, and blood vessel disease. Each factor adds points to the total score. The score ranges from 0 to 9. A higher score means a higher chance of stroke each year. Doctors use this score to decide if a patient needs blood-thinning medicine (anticoagulation) to help prevent a stroke.
Use the calculator below to select each risk factor, then press "Calculate" to see the total score, the estimated annual stroke risk, and a guideline-based treatment recommendation.
How to Use Our CHA2DS2-VASc Calculator
Answer "Yes" or "No" to each health question below about your patient. The calculator will give you a score from 0 to 9, a risk level, the yearly stroke risk, and a guide on whether blood thinners are needed.
Congestive Heart Failure: Select "Yes" if the patient has heart failure or a left ventricular ejection fraction of 40% or less.4
Hypertension: Select "Yes" if the patient has blood pressure above 140/90 mmHg on two or more readings, or takes blood pressure medicine.4
Age ≥75 Years: Select "Yes" if the patient is 75 years old or older. This adds 2 points. Picking "Yes" here will set "Age 65–74" to "No" since both cannot be true at once.
Diabetes Mellitus: Select "Yes" if the patient has diabetes or takes medicine to lower blood sugar.4
Stroke / TIA / Thromboembolism: Select "Yes" if the patient has ever had a stroke, mini-stroke (TIA), or a blood clot event. This adds 2 points.
Vascular Disease: Select "Yes" if the patient has had a heart attack, peripheral artery disease, or complex aortic plaque.4
Age 65–74 Years: Select "Yes" if the patient is between 65 and 74 years old. Picking "Yes" here will set "Age ≥75" to "No" since both cannot be true at once.
Sex Category (Female): Select "Yes" if the patient is female. Note that female sex alone as the only risk factor does not call for blood thinner therapy.
After you fill in each field, press "Calculate" to see the full results, including a score breakdown, step-by-step solution, and a stroke risk chart.
What Is the CHA2DS2-VASc Score?
The CHA2DS2-VASc score is a simple tool doctors use to figure out how likely a person with atrial fibrillation (an irregular heartbeat, also called AFib) is to have a stroke. Most strokes happen when blood flow to the brain is blocked by a blood clot or by fatty deposits called plaque. People with AFib are at higher risk for stroke because blood can pool in the heart, which raises the chance that clots form.
How Does It Work?
The score adds up points based on specific health conditions and personal traits. Each letter in the name stands for a risk factor:
- C: Congestive heart failure (the heart is too weak to pump well)
- H: High blood pressure
- A2: Age 75 or older (worth 2 points because age is a strong risk factor)2
- D: Diabetes
- S2: Prior stroke, TIA, or blood clot (worth 2 points because a past stroke greatly raises the chance of another)
- V: Vascular disease (problems in blood vessels, like a past heart attack)
- A: Age 65 to 74
- Sc: Sex category (being female adds 1 point)
The total score ranges from 0 to 9. A higher score means a higher chance of stroke each year.
What Do the Results Mean?
A score of 0 means the risk is low, and blood-thinning medicine (called anticoagulation) is usually not needed. A score of 1 puts a person in a gray area, so a doctor may or may not recommend treatment depending on the full picture. The 2023 atrial fibrillation guideline keys the decision to risk rather than to the score itself: in patients with an estimated annual risk of stroke or thromboembolic events of 2% or more, therapy should be selected on that risk.2 In the guideline, that level matches a score of 2 or more in men and 3 or more in women.2
It is important to know that a score of 1 from female sex alone does not count the same way. Current guidelines say being female by itself, with no other risk factors, does not require blood thinners.
Why Is This Score Important?
Atrial fibrillation affects millions of people worldwide. In meta-analyses, atrial fibrillation carries a 2.4-fold risk of stroke.2 The CHA2DS2-VASc score helps doctors decide who benefits most from blood-thinning drugs. These drugs lower stroke risk but can cause bleeding, so they should only be used when the benefit is clear. This score makes that decision more straightforward.
When prescribing anticoagulants, checking kidney function with a GFR Calculator is essential for proper dose adjustments.
Note: This calculator is for educational purposes only. Always talk to a doctor before making decisions about medication or treatment.