CHA2DS2-VASc Stroke Risk Calculator

Components of the CHA2DS2-VASc score

The name CHA2DS2-VASc is a mnemonic for the individual stroke risk factors that are included in the score. Each factor contributes a fixed number of points, and the total score ranges from 0 to 9.

• C – Congestive heart failure (1 point): History of clinical heart failure or reduced left ventricular systolic function.
• H – Hypertension (1 point): History of high blood pressure, whether or not it is currently controlled with medication.
• A₂ – Age (2 points if ≥75 years; 1 point if 65–74 years): Older age is a strong, graded risk factor for stroke.
• D – Diabetes mellitus (1 point): History of type 1 or type 2 diabetes.
• S₂ – Prior stroke or TIA (2 points): Previous ischemic stroke, transient ischemic attack, or systemic embolism.
• V – Vascular disease (1 point): Prior myocardial infarction, peripheral artery disease, or aortic plaque.
• Sc – Sex category (female sex, 1 point): Female sex adds one point, but its interpretation differs from other items (explained below).

The points from all present risk factors are added to obtain the total CHA2DS2-VASc score.

Formula and calculation

Mathematically, the CHA2DS2-VASc score is a simple weighted sum of binary risk factors. Each factor is either present (1) or absent (0), and it is multiplied by a fixed weight that corresponds to its point value.

In symbolic form:

where each term is either 0 (risk factor absent) or 1 (risk factor present), and the multipliers of 2 indicate items that contribute two points instead of one (age ≥75 and prior stroke/TIA).

In practice, the calculator performs the following steps:

1. Checks the age entered. If age is 75 years or older, it adds 2 points for age. If age is between 65 and 74 years inclusive, it adds 1 point. If age is under 65, it adds 0 age points.
2. Adds 1 point for each of the following that are selected: congestive heart failure, hypertension, diabetes mellitus, vascular disease, and female sex.
3. Adds 2 points if there is a history of prior stroke, TIA, or systemic embolism.
4. Sums all points to give the final CHA2DS2-VASc score between 0 and 9.

How to use this calculator

To use the calculator on this page:

1. Enter your age in completed years. The tool applies the correct point value automatically based on the age cutoffs of 65 and 75 years.
2. Select each condition that applies from the checklist: congestive heart failure, hypertension, diabetes, prior stroke or TIA, and vascular disease. If you are unsure about a diagnosis, review your medical record or speak with your clinician rather than guessing.
3. Indicate sex category by checking the box if the patient is female. This field is used exactly as defined in the original CHA2DS2-VASc model.
4. Submit the form to see your total CHA2DS2-VASc score and an approximate category of annual stroke risk.

The calculator only uses information you enter during this session and does not replace a full clinical assessment.

Interpreting your CHA2DS2-VASc score

The CHA2DS2-VASc score estimates annual stroke risk at a population level. Individual risk can be higher or lower. Different professional guidelines (for example, from European or North American societies) may use slightly different thresholds for recommending oral anticoagulation, and they also consider bleeding risk, patient values, and other clinical details.

Typical interpretation patterns include the following, especially for patients with non-valvular atrial fibrillation:

• Score 0 in males or 1 in females: Very low estimated stroke risk. Many guidelines consider these patients as not needing routine anticoagulation, assuming no other risk modifiers.
• Score 1 in males or 2 in females: Low-to-intermediate risk. Some guidelines suggest that anticoagulation may be considered, particularly if additional risk factors are present or if the added point is not solely from female sex.
• Score ≥2 in males or ≥3 in females: Higher risk range in which long-term oral anticoagulation is often recommended unless bleeding risk is prohibitive.

These thresholds are simplified and may not apply to every person. Scores are used in combination with a structured bleeding risk assessment (such as HAS-BLED) and clinical judgment. The calculator on this page does not estimate bleeding risk.

Estimated annual stroke risk increases with the score. While exact numbers vary by study and population, some commonly cited approximate risks for untreated patients include:

• CHA2DS2-VASc 0: often around 0.2–0.5% per year
• CHA2DS2-VASc 1: often around 0.6–1.3% per year
• CHA2DS2-VASc 2: often around 2–3% per year
• CHA2DS2-VASc ≥1: progressively higher, reaching double-digit percentages at the highest scores

These figures are approximate ranges drawn from cohort studies and are not guarantees for any single patient.

Worked example

Consider an example patient to illustrate how the score is calculated and interpreted.

Patient profile:

• Age: 78 years
• Sex: female
• Congestive heart failure: yes (history of systolic heart failure)
• Hypertension: yes (on treatment)
• Diabetes mellitus: no
• Prior stroke or TIA: no
• Vascular disease: yes (prior myocardial infarction)

Step-by-step scoring:

1. Age 78 years → age ≥75: 2 points
2. Congestive heart failure present: 1 point
3. Hypertension present: 1 point
4. Diabetes mellitus absent: 0 points
5. No prior stroke or TIA: 0 points
6. Vascular disease present: 1 point
7. Female sex: 1 point

Total CHA2DS2-VASc score: 2 + 1 + 1 + 0 + 0 + 1 + 1 = 6.

A score of 6 corresponds to a substantially elevated annual stroke risk if the patient is not treated with anticoagulation, often in the range of several percent per year or more, depending on the population studied. In current guidelines, this level of risk would usually lead to a strong consideration or recommendation for long-term oral anticoagulant therapy, provided the bleeding risk is acceptable and there are no major contraindications.

Importantly, the calculator itself cannot decide whether this particular patient should receive anticoagulation. That choice depends on factors such as kidney function, previous bleeding, fall risk, concomitant medications, and the patient’s preferences after informed discussion.

Comparison: CHA2DS2-VASc vs. selected alternatives

Several tools are used alongside or in comparison to CHA2DS2-VASc when assessing people with atrial fibrillation. The table below summarizes the role of CHA2DS2-VASc relative to some commonly referenced concepts.

Limitations and assumptions

Like all clinical prediction tools, CHA2DS2-VASc has important limitations and relies on several assumptions:

• Developed for atrial fibrillation: The score was derived and validated in patients with atrial fibrillation (usually non-valvular). It should not be assumed to apply to other heart rhythms or conditions without AF.
• Population-level, not individual prediction: The risk percentages associated with each score come from groups of patients followed over time. They describe average risk, not an exact forecast for any particular person.
• Female sex point is context-dependent: In some guidelines, female sex alone (without other risk factors) does not usually trigger treatment, even though it adds one point. It is mainly considered a risk modifier when another factor is present.
• Does not measure bleeding risk: CHA2DS2-VASc only estimates stroke risk. Safe decision-making about anticoagulation also requires assessing bleeding risk, fall risk, kidney and liver function, and many other factors that are not included here.
• Assumes accurate clinical information: Misclassification of diagnoses (for example, uncertain history of TIA or vascular disease) can lead to incorrect scores. If you are unsure whether a risk factor applies, review medical records or ask a clinician.
• Guideline differences: Professional societies may recommend different thresholds or approaches for starting anticoagulation, especially as new evidence emerges. The interpretation notes on this page are simplified and may not match every guideline or country.
• No automatic treatment advice: This tool does not provide individualized medical advice, diagnose disease, or recommend specific drugs or doses. It is not a substitute for an in-person evaluation.
• Data and evidence can change: Risk estimates are based on studies conducted in specific populations and eras. As treatment patterns and demographics change, the exact numerical risk at each score may also shift.

Because of these limitations, results from this calculator should always be interpreted cautiously and in context.

When to seek medical advice

If you have atrial fibrillation or suspect an irregular heartbeat, you should discuss your situation with a healthcare professional. High CHA2DS2-VASc scores generally indicate that stroke prevention strategies, including anticoagulation, deserve careful consideration. Low scores do not rule out the need for follow-up, especially if your health status changes over time.

You should seek prompt medical attention if you experience possible stroke symptoms such as sudden weakness, facial droop, difficulty speaking, loss of vision, or sudden imbalance. Do not use this or any online calculator to decide whether to delay emergency care.

Evidence and references (overview)

The CHA2DS2-VASc score is recommended or endorsed by major cardiology and stroke guidelines, including those from European and North American professional societies. Its components and weightings were developed by analyzing large cohorts of patients with atrial fibrillation and identifying clinical characteristics that predicted future stroke or systemic embolism.

While this page does not reproduce full reference lists, the score is based on widely cited work that has been replicated in multiple settings. For detailed evidence, clinicians can review contemporary guidelines on the management of atrial fibrillation and original validation studies of the CHA2DS2-VASc model.

As with any clinical research, new data may refine how these tools are used over time. Always check up-to-date local and international guidelines when applying risk scores in practice.