What this calculator does
The CHA₂DS₂-VASc calculator adds up a standard, published set of clinical risk factors used to estimate stroke risk in people with atrial fibrillation, an irregular heart rhythm. Each factor carries a fixed point value set out in the original scoring criteria: congestive heart failure, hypertension, age, diabetes, prior stroke, vascular disease and sex each contribute a defined number of points, adding up to a score out of 9.
This is a clinical decision-support tool used by doctors alongside other information, not a self-diagnosis calculator. A higher score is associated with higher stroke risk in people who already have a confirmed diagnosis of atrial fibrillation, and the score is one input a doctor weighs when discussing whether blood-thinning medication is appropriate. It says nothing on its own about whether someone has atrial fibrillation in the first place, and any score should be discussed with a doctor rather than acted on directly.
The formula
Each yes/no risk factor entered adds its fixed point value: 1 point each for congestive heart failure or reduced heart function, hypertension, diabetes and vascular disease; 2 points for a prior stroke, TIA or blood clot; and 1 point for female sex. Age is scored in bands rather than as a yes/no answer: 2 points for age 75 or over, 1 point for age 65 to 74, and 0 points under 65. The total is the sum of every point earned, out of a maximum of 9.
| Term | Meaning |
|---|---|
| CHA₂DS₂-VASc | The acronym for the criteria scored: Congestive heart failure, Hypertension, Age ≥75 (2 points), Diabetes, prior Stroke/TIA (2 points), Vascular disease, Age 65 to 74, and Sex category female. |
| TIA | Transient ischaemic attack, a temporary stroke-like episode sometimes called a mini-stroke, scored the same as a prior stroke. |
| Vascular disease | A prior heart attack, peripheral artery disease, or significant plaque in the aorta, each counted as one qualifying condition here. |
The inputs explained
| Field | What to enter |
|---|---|
| Age (years) | Age in whole years, which sets the age-band points automatically. |
| Sex | Sex, since female sex carries one point in the published criteria. |
| Congestive heart failure or LV dysfunction | Whether there is a history of congestive heart failure or a reduced heart pumping function (reduced ejection fraction). |
| Hypertension | Whether there is a diagnosis of high blood pressure, treated or untreated. |
| Diabetes mellitus | Whether there is a diagnosis of diabetes mellitus, of any type. |
| Prior stroke, TIA or thromboembolism | Whether there has been a prior stroke, TIA, or other blood clot event (thromboembolism). |
| Vascular disease (prior MI, peripheral artery disease or aortic plaque) | Whether there is known vascular disease: a prior heart attack, peripheral artery disease, or aortic plaque. |
When to use it
Discussing anticoagulation with a doctor
A calculated score is something a doctor typically reviews alongside bleeding-risk factors and a person's own preferences before recommending, or not recommending, blood-thinning medication for atrial fibrillation.
Understanding how a score is made up
Seeing which individual factors are contributing points, rather than only the total, shows which parts of the score come from fixed characteristics like age and sex versus modifiable or treatable conditions.
Tracking a score as circumstances change
A score can change over time, for instance if hypertension is newly diagnosed or someone crosses an age threshold, which is worth recalculating rather than assuming a past score still applies.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How age alone changes the score, with no other risk factors
A male with none of the other risk factors present, across a range of ages, showing how age band points alone build the score.
| Age | CHA₂DS₂-VASc score | Age band points |
|---|---|---|
| 50 years | 0 of 9 | 0 (under 65) |
| 60 years | 0 of 9 | 0 (under 65) |
| 65 years | 1 of 9 | 1 (age 65 to 74) |
| 70 years | 1 of 9 | 1 (age 65 to 74) |
| 75 years | 2 of 9 | 2 (age 75 or over) |
| 80 years | 2 of 9 | 2 (age 75 or over) |
| 90 years | 2 of 9 | 2 (age 75 or over) |
How sex changes the score, with hypertension and diabetes present
Hypertension and diabetes both present, comparing male and female at two different ages.
Questions
What does a CHA₂DS₂-VASc score actually measure?
It is a standardised way of counting established stroke-risk factors in people already diagnosed with atrial fibrillation. It does not diagnose atrial fibrillation itself, and it is only one part of the wider clinical picture a doctor considers.
Is a higher score always worse?
A higher score reflects more accumulated risk factors and is associated with higher stroke risk in atrial fibrillation, but the score alone does not set a treatment decision. A doctor weighs it alongside bleeding risk and individual circumstances.
Why is age scored differently to the other criteria?
Age is scored in bands because stroke risk from age itself is not simply present or absent: it rises further once someone reaches 75, which the published scoring criteria capture with a higher point value than the 65 to 74 band.
Should I use this score to decide on my own treatment?
No. This calculator reproduces a published clinical scoring tool for information, but decisions about anticoagulation or other treatment for atrial fibrillation should be made with a doctor, who can weigh this score against bleeding risk and the rest of your medical history.
For a kidney-function estimate that uses a similarly fixed, published clinical formula, see the eGFR calculator. For blood pressure context relevant to the hypertension criterion here, see the mean arterial pressure calculator.