CHA2DS2-VASc Score Calculator
Add up stroke risk points for atrial fibrillation from age, heart failure, hypertension, diabetes, stroke history, vascular disease, and sex.
What it does
Atrial fibrillation raises the odds of a stroke because blood can pool in the upper chambers of the heart and form clots. The CHA2DS2-VASc score turns that risk into a short checklist: eight familiar clinical items, each worth 1 or 2 points, added into a number from 0 to 9.
The name is a memory device: C for heart failure, H for hypertension, A2 for age 75 or over (2 points), D for diabetes, S2 for prior stroke or TIA (2 points), V for vascular disease, A for age 65 to 74, and Sc for female sex.
Guidelines use the total to decide who should be offered blood thinners. NICE advises offering anticoagulation with a direct-acting oral anticoagulant once the score reaches 2 or more. US guidance acts on 2 or more in men and 3 or more in women, which is the same idea with the sex point treated carefully.
One quirk trips people up: female sex adds 1 point, but a score of 1 that comes only from sex does not by itself flag extra risk. In practice, a woman with sex as her only point is managed like a man with a score of 0.
This page scores the same items the guidelines list, shows the arithmetic for a worked example, and answers the questions people ask before using the number with a clinician.
How to use
- Pick the age band: under 65, 65 to 74, or 75 and over.
- Answer each clinical item: heart failure, high blood pressure, diabetes, prior stroke or TIA, and vascular disease.
- Choose sex, which adds 1 point for women.
- Read the total together with the risk band and the usual next step.
- If the score is 1 and the only point is female sex, treat it as low risk.
- Take the result to the clinician who manages the atrial fibrillation; the score does not prescribe anything on its own.
Formula
- Age
- 2 points at 75 or over, 1 point at 65 to 74, 0 below 65.
- S2
- Prior stroke, TIA, or thromboembolism, worth 2 points.
- Others
- Heart failure, hypertension, diabetes, vascular disease, and female sex, 1 point each.
The maximum is 9: 2 for age 75 or over, 2 for prior stroke, and 5 single points. NICE NG196 says to offer anticoagulation with a direct-acting oral anticoagulant at a score of 2 or more. A woman whose only point comes from sex is often counted at 2 or more only when another item is present, which is why US guidance uses a threshold of 3 for women.
Worked example
Example: 70-year-old woman with high blood pressure
Age 65 to 74, hypertension, no other items, female (defaults).
- Age 65 to 74: 1 point.
- High blood pressure: 1 point.
- Heart failure, diabetes, stroke history, and vascular disease: 0 points.
- Female sex: 1 point.
- Total: 3 of 9. That is 2 or more, so guidelines would usually move to a conversation about anticoagulation.
Reference table
| Item | Points |
|---|---|
| Age 75 or over | 2 |
| Age 65 to 74 | 1 |
| Heart failure | 1 |
| High blood pressure | 1 |
| Diabetes | 1 |
| Prior stroke, TIA, or thromboembolism | 2 |
| Vascular disease | 1 |
| Female sex | 1 |
| Maximum total | 9 |
Limits
- Built for atrial fibrillation. It does not score stroke risk after a mechanical valve, in valvular disease, or in heart failure without AF.
- The score sorts groups of patients; it cannot predict an individual stroke.
- Bleeding risk is a separate question. Clinicians weigh it with tools like HAS-BLED before prescribing.
- Kidney function, drug interactions, and patient preference all shape the final plan.
Common mistakes
- Counting female sex twice, once as a factor and once as an adjusted threshold.
- Scoring a 60-year-old with no risk factors as low but skipping the diabetes question.
- Forgetting that prior stroke counts 2 and age 75 or over counts 2, not 1.
- Using the score for flutter or other rhythms without checking the guideline scope.
- Reading score 1 in a woman as high risk when the single point is sex alone.
Try it yourself
Quick checks. Answers sit tucked under each question.
A 78-year-old man with diabetes and a prior stroke. What is the score?
2 (age) + 1 (diabetes) + 2 (stroke) = 5 of 9.
A 60-year-old man with no listed items?
0 of 9. Low risk band.
A 70-year-old woman with hypertension only?
1 + 1 + 1 = 3 of 9. Anticoagulation is usually discussed.
Questions
What score needs anticoagulation?
NICE NG196 says to offer a direct-acting oral anticoagulant at a CHA2DS2-VASc score of 2 or more. US guidance uses 2 or more in men and 3 or more in women. The score informs the decision; bleeding risk and preference shape it.
Why does female sex count only 1 point?
Women have a slightly higher background stroke risk in AF, but the extra point alone does not change management, so a woman with sex as her only point is treated like a man with score 0.
Is this the same as the old CHADS2 score?
No. CHADS2 ran 0 to 6 with fewer items. CHA2DS2-VASc adds age 65 to 74, vascular disease, and female sex, and splits age into two bands, which improves sorting at low scores.
What counts as vascular disease?
Prior heart attack, peripheral artery disease, or plaque in the aorta. Ask the clinician if you are unsure; this affects 1 point.
What happens after a high score?
Usually a conversation about anticoagulation, weighing stroke risk against bleeding risk, kidney function, interactions, and what matters to the patient.
Can my score change over time?
Yes. Each birthday can add a point and each new diagnosis can add points, so the score is recalculated as things change.
Sources
- NICE guideline NG196: atrial fibrillation, offer anticoagulation at CHA2DS2-VASc 2 or more
- 2023 ACC/AHA/ACCP/HRS guideline for the diagnosis and management of atrial fibrillation