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CHA2DS2-VASc Score Calculator — AFib Stroke Risk

Calculate CHA2DS2-VASc score for atrial fibrillation stroke risk. Checkbox-based scoring with annual stroke risk % and anticoagulation context.

Auto-scored: under 65 = 0 pts, 65–74 = 1 pt, 75+ = 2 pts

CHA₂DS₂-VASc Score

1

out of a maximum of 9

Low–Moderate Risk

Estimated annual ischemic stroke risk: 1.3% (untreated, based on the reference validation cohort).

ScoreAnnual Stroke Risk
00%
11.3%← Result
22.2%
33.2%
44%
56.7%
69.8%
79.6%
86.7%
915.2%

Note: scores 7 and 8 show a slightly lower risk than score 6 in the original validation cohort — a known small-sample artifact at high scores, not a genuine reversal of risk. Treat scores 6–9 as uniformly high-risk.

CHA₂DS₂-VASc: Congestive heart failure (1) + Hypertension (1) + Age ≥75 (2) + Diabetes (1) + Stroke/TIA/thromboembolism (2) + Vascular disease (1) + Age 65–74 (1) + Sex category female (1), max 9. This is a clinical decision-support tool, not a substitute for medical advice — actual anticoagulation decisions require a physician weighing this score against bleeding risk (e.g. HAS-BLED score) and individual patient factors.
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Reference Values

Last verified:
Category Range What It Means Status
Congestive heart failure / LV dysfunction +1 point History of congestive heart failure symptoms, or objective evidence of reduced left ventricular ejection fraction on imaging. Okay
Hypertension +1 point Resting blood pressure consistently above 140/90 mmHg on at least two occasions, or currently on antihypertensive medication. Okay
Age 75 or older +2 points The single largest point contributor. Uses the ≥75 bracket instead of the 65–74 bracket — never both at once. Poor
Diabetes mellitus +1 point Fasting glucose >125 mg/dL (7 mmol/L), or treatment with oral hypoglycemics and/or insulin. Okay
Prior stroke, TIA, or thromboembolism +2 points Any prior ischemic stroke, transient ischemic attack, or systemic thromboembolic event. The strongest single predictor of future stroke risk in this score. Poor
Vascular disease +1 point Prior myocardial infarction, peripheral artery disease, or aortic plaque on imaging. Okay
Age 65–74 +1 point Middle age bracket. Mutually exclusive with the ≥75 bracket — a patient is scored in only one age bracket. Okay
Sex category — female +1 point Female sex is an independent risk-modifying factor in the original validation cohort, not a comorbidity — it only adds risk in the presence of at least one other risk factor in most modern interpretations. Okay
Score 0 ★ 0% annual stroke risk Lowest-risk tier. Guidelines generally recommend no antithrombotic therapy for a male with score 0 or a female with score 1 (sex-only point). ★ Best
Score 1 1.3% annual stroke risk Low risk — anticoagulation is typically not mandated and is individualized. Good
Score 2 2.2% annual stroke risk Anticoagulation is generally recommended for men at this score (or women at score 3, since 1 point is from sex alone). Good
Score 3 3.2% annual stroke risk Moderate risk — anticoagulation recommended in most guidelines. Okay
Score 4 4.0% annual stroke risk Moderate-high risk. Okay
Score 5 6.7% annual stroke risk High risk. Poor
Score 6 9.8% annual stroke risk High risk — the highest single point on the reference curve. Poor
Score 7 9.6% annual stroke risk High risk. Slightly below score 6 in the original cohort — a known small-sample artifact at high scores, not a clinical reversal of risk. Poor
Score 8 6.7% annual stroke risk High risk. Lower than scores 6–7 in the published cohort due to very few patients reaching this score — treat scores 6–9 as uniformly "high risk" rather than reading the dip as meaningful. Poor
Score 9 15.2% annual stroke risk Maximum possible score — highest annual stroke risk in the reference table. Poor

Source: Point weights and annual stroke risk percentages from the CHA2DS2-VASc scoring system as validated in Lip GYH et al., Chest 2010 ("Refining Clinical Risk Stratification..."), and cross-referenced against the MDCalc CHA2DS2-VASc Score reference table and NHS CPD Connect clinical scoring guidance. The non-monotonic dip at scores 7–8 is a documented feature of the original validation cohort's small patient counts at high scores, reproduced here as published rather than smoothed.

Worked Examples

Low-Risk Younger Male

Age
58
Sex
Male
CHF/LV dysfunction
No
Hypertension
No
Diabetes
No
Prior stroke/TIA
No
Vascular disease
No
Score 0 — 0% annual stroke risk

No risk factors and under 65, so no points from any category. Guidelines generally recommend no antithrombotic therapy at this score.

Middle-Aged Woman With Hypertension Only

Age
68
Sex
Female
CHF/LV dysfunction
No
Hypertension
Yes
Diabetes
No
Prior stroke/TIA
No
Vascular disease
No
Score 3 — 3.2% annual stroke risk

Age 65–74 (+1) + Hypertension (+1) + Female sex (+1) = 3. Anticoagulation is typically recommended at this score.

Older Male With Diabetes and Vascular Disease

Age
77
Sex
Male
CHF/LV dysfunction
No
Hypertension
Yes
Diabetes
Yes
Prior stroke/TIA
No
Vascular disease
Yes
Score 5 — 6.7% annual stroke risk

Age ≥75 (+2) + Hypertension (+1) + Diabetes (+1) + Vascular disease (+1) = 5. High-risk category — anticoagulation strongly recommended pending bleeding-risk assessment.

Prior Stroke Case

Age
72
Sex
Female
CHF/LV dysfunction
Yes
Hypertension
Yes
Diabetes
No
Prior stroke/TIA
Yes
Vascular disease
No
Score 6 — 9.8% annual stroke risk

CHF (+1) + Hypertension (+1) + Age 65–74 (+1) + Prior stroke/TIA (+2) + Female sex (+1) = 6. The highest point on the annual risk curve in the reference table.

Maximum Score

Age
80
Sex
Female
CHF/LV dysfunction
Yes
Hypertension
Yes
Diabetes
Yes
Prior stroke/TIA
Yes
Vascular disease
Yes
Score 9 — 15.2% annual stroke risk

CHF (+1) + Hypertension (+1) + Age ≥75 (+2) + Diabetes (+1) + Prior stroke/TIA (+2) + Vascular disease (+1) + Female sex (+1) = 9, the maximum possible score.

How to Use This Calculator

  1. 1

    Enter age

    Type the patient's age in years. The calculator automatically applies the correct age bracket — 0 points under 65, 1 point for 65–74, 2 points for 75 and older — so you never have to choose between overlapping age checkboxes.

  2. 2

    Select sex

    Female sex adds 1 point, reflecting its role as an independent stroke risk modifier in the validation studies behind this score.

  3. 3

    Check each risk factor that applies

    Congestive heart failure/LV dysfunction, hypertension, diabetes, prior stroke/TIA/thromboembolism, and vascular disease each add points as shown next to the checkbox.

  4. 4

    Read the score and annual stroke risk

    The total score (0–9) updates instantly and maps to a published annual stroke risk percentage, shown alongside the full reference table for context.

What Each Value Means

CHA2DS2-VASc Score (points)
A 0–9 point clinical score estimating annual ischemic stroke risk in patients with non-valvular atrial fibrillation, built from eight weighted risk factors. Widely adopted by cardiology and stroke-prevention guidelines to guide anticoagulation decisions.
Annual Stroke Risk (percent per year)
The published percentage likelihood of an ischemic stroke within one year for an untreated patient at a given CHA2DS2-VASc score, drawn from the score's original validation cohort.
Age Bracket Points (points)
Age 65–74 contributes 1 point; age 75 or older contributes 2 points. The two brackets are mutually exclusive — a patient is scored in only one.
Sex Category Point (points)
Female sex contributes 1 point as an independent stroke risk modifier, not a comorbidity — most modern guideline interpretations only count it as risk-increasing when at least one other factor is also present.

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Frequently Asked Questions

What does the CHA2DS2-VASc score measure?
It estimates the annual risk of ischemic stroke in patients with non-valvular atrial fibrillation, based on eight weighted risk factors: congestive heart failure, hypertension, age, diabetes, prior stroke/TIA, vascular disease, and sex. The total score (0–9) maps to a published annual stroke risk percentage, which clinicians use alongside bleeding-risk tools to decide whether anticoagulation is warranted.
Why is age split into two brackets instead of one checkbox?
The score awards 1 point for age 65–74 and 2 points for age 75 or older — these brackets are mutually exclusive, so a patient is scored in only one of them, never both. This calculator uses a single age input and automatically applies the correct bracket, which avoids the contradictory situation of checking both an 'age 65-74' and an 'age 75+' box in a manual checklist.
Why does a woman get an extra point just for her sex?
The original CHA2DS2-VASc validation studies found that female sex was an independent risk-modifying factor for stroke in atrial fibrillation, not a comorbidity like hypertension or diabetes. Because of this, most contemporary guidelines only count the sex point as risk-increasing when at least one other risk factor is also present — a woman with otherwise zero risk factors is generally treated the same as a man with a score of zero, despite technically scoring a 1.
Why do scores 7 and 8 show lower stroke risk than score 6 in the reference table?
This dip is a well-documented quirk of the original validation cohort, not a data-entry error or a real reversal of risk. Very few patients in the source population actually reached scores of 7, 8, or 9, so the risk percentages at those points are statistically less stable than the risk percentages for the much more common low-to-mid scores. Clinically, scores 6 through 9 are all treated as "high risk" — the exact percentage ordering among them isn't meaningful.
Does a high CHA2DS2-VASc score automatically mean I need blood thinners?
Not automatically. The score estimates stroke risk if a patient goes untreated, but the anticoagulation decision also has to weigh bleeding risk — typically assessed with the HAS-BLED score — plus the patient's kidney function, fall risk, medication interactions, and personal preference. A high CHA2DS2-VASc score makes anticoagulation more likely to be recommended, but the final call is always a physician's, balancing stroke prevention against bleeding harm.