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About this tool
Estimate 10-year stroke risk using CHA₂DS₂-VASc scoring for atrial fibrillation patients with clinical risk factor analysis.
This stroke risk calculator scores the CHA₂DS₂-VASc model used in atrial fibrillation — congestive heart failure, hypertension, age 65–74, diabetes, vascular disease and female sex each add 1 point, while age ≥ 75 and a prior stroke, TIA or thromboembolism add 2 — for a total out of 9, then maps that total to an estimated annual stroke rate. You can also switch to the older CHADS₂ model and score HAS-BLED alongside it to see bleeding risk in the same view. It is an educational reference for patients and students, not a substitute for a clinician's assessment.
Open Stroke Risk Calculator on AltFTool — it loads instantly in your browser.
Choose the CHA₂DS₂-VASc or CHADS₂ tab, then tick the Risk Factors: Congestive Heart Failure, Hypertension, Age ≥ 75 years, Diabetes Mellitus and Prior Stroke / TIA / Thromboembolism, plus Vascular Disease, Age 65–74 years and Sex Category (Female) under VASc Additions.
Tick whatever applies under HAS-BLED (Bleeding Risk) — Uncontrolled Hypertension, Labile INR (if on warfarin), Antiplatelet / NSAID Use and the rest — then press Assess Risk.
Read the score with its risk band and annual rate, the Bleeding Score out of 9 and the Score Interpretation table, then press Copy Report, or Download to save Stroke_Risk_Report_<score>.txt.
Toggle between CHA₂DS₂-VASc and the older CHADS₂ to see how adding vascular disease, age 65–74 and sex category changes the total.
A built-in HAS-BLED tally shows the other half of the anticoagulation decision instead of the stroke score alone.
Copy or download a plain-text report listing every risk factor selected, the score, the risk band and its interpretation.
Guidelines generally recommend oral anticoagulation from a score of 2 or more, treat 1 as an individual risk-benefit discussion, and consider no anticoagulation at 0. The final decision belongs to your doctor, who will weigh bleeding risk, kidney function and your own preferences.
Only two: age 75 or older, and a prior stroke, TIA or systemic embolism. Heart failure, hypertension, age 65–74, diabetes, vascular disease and female sex are worth 1 point each, giving a maximum of 9.
For CHA₂DS₂-VASc: roughly 0% a year at a score of 0, about 1.3% at 1, 2.2% at 2, 3.2% at 3, 4.0% at 4, then 6.7%–15% from 5 upward as more risk factors stack up. The older CHADS₂ model uses a different, generally higher-looking scale that only runs 0–6: about 1.9% at 0, 2.8% at 1, 4.0% at 2, 5.9% at 3, 8.5% at 4, 12.5% at 5 and 18.2% at 6. These are population estimates from each model's own published cohort, so your personal risk can differ.
A HAS-BLED score of 3 or more flags high bleeding risk on anticoagulation. It is not a reason to withhold treatment on its own — it is a prompt to correct modifiable factors such as uncontrolled blood pressure above 160 mmHg, NSAID use or heavy alcohol intake, and to review the patient more often.
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