CHA2DS2-VASc Calculator
CHA2DS2-VASc stroke risk in atrial fibrillation, with the annual event rate per score from a 73,538-patient untreated cohort and the sex-free CHA2DS2-VA variant.
CHA2DS2-VASc Calculator: with the default inputs, cha₂ds₂-vasc score is 2.
65 to 74 scores 1; 75 and over scores 2.
1 point.
1 point.
1 point.
2 points. Includes peripheral arterial embolism and pulmonary embolism.
1 point. Myocardial infarction, peripheral artery disease or aortic plaque.
Out of a maximum of 9.
- CHA₂DS₂-VA score
- 2The same score without the sex category, as used in the 2024 ESC guideline. Maximum 8.
- Thromboembolic events per 100 person-years
- 3.71At this score, in untreated patients in the Danish cohort — roughly, events per 100 patients per year.
- 95% confidence interval for that rate
- 3.36 to 4.09 per 100 person-years
- Risk band used in that cohort
- High risk (score 2 to 9)
- What NICE recommends at this score
- NICE recommends offering anticoagulation with a direct-acting oral anticoagulant at a CHA₂DS₂-VASc score of 2 or above, taking bleeding risk into account.
Assumptions
- This is an estimate for education. It does not diagnose anything and does not replace clinical judgement.
- Scoring follows the definition stated in Olesen et al., BMJ 2011: 1 point each for heart failure, hypertension, diabetes, vascular disease, age 65-74 and female sex; 2 points each for previous thromboembolism and age 75 or over.
- Event rates are hospital admission and death due to thromboembolism at one year in 73,538 Danish patients with non-valvular atrial fibrillation not receiving a vitamin K antagonist or heparin, followed from 1997. They are population rates from a cohort predating direct-acting oral anticoagulants.
- Anticoagulation thresholds quoted are NICE NG196's; other guidelines set them differently, and the 2024 ESC guideline uses the sex-free CHA₂DS₂-VA score.
- The score applies to non-valvular atrial fibrillation and does not cover moderate-to-severe mitral stenosis or mechanical heart valves.
- It estimates thromboembolic risk only and says nothing about bleeding risk.
| Risk factor | Points | Scored |
|---|---|---|
| C — Congestive heart failure | 1 | |
| H — Hypertension | 1 | yes |
| A₂ — Age 75 or over | 2 | |
| D — Diabetes mellitus | 1 | |
| S₂ — Previous stroke, TIA or thromboembolism | 2 | |
| V — Vascular disease | 1 | |
| A — Age 65 to 74 | 1 | yes |
| Sc — Sex category (female) | 1 |
Maximum 9. Age contributes either 1 point (65-74) or 2 points (75 and over), never both.
| Score | Events per 100 person-years | 95% CI | |
|---|---|---|---|
| 0 | 0.78 | 0.58 to 1.04 | |
| 1 | 2.01 | 1.70 to 2.36 | |
| 2 | 3.71 | 3.36 to 4.09 | ← this score |
| 3 | 5.92 | 5.53 to 6.34 | |
| 4 | 9.27 | 8.71 to 9.86 | |
| 5 | 15.26 | 14.35 to 16.24 | |
| 6 | 19.74 | 18.21 to 21.41 | |
| 7 | 21.5 | 18.75 to 24.64 | |
| 8 | 22.38 | 16.29 to 30.76 | |
| 9 | 23.64 | 10.62 to 52.61 |
Hospital admission and death due to thromboembolism at one year of follow-up, in 73,538 Danish patients with non-valvular atrial fibrillation not receiving a vitamin K antagonist or heparin (Olesen et al., BMJ 2011, Table 2). Rates in that cohort predate direct-acting oral anticoagulants.
How this is worked out
The formula
CHA₂DS₂-VASc, maximum 9 points: C Congestive heart failure 1 H Hypertension 1 A₂ Age 75 or over 2 D Diabetes mellitus 1 S₂ Previous stroke, TIA or thromboembolism 2 V Vascular disease 1 A Age 65 to 74 1 Sc Sex category (female) 1 CHA₂DS₂-VA is the same score with the sex category removed (maximum 8).
Open How it’s calculated above to see this worked through with your own numbers.
What you enter
- Age
- 65 to 74 scores 1; 75 and over scores 2.from 18 to 120 · whole numbers only · defaults to 72
- Sex
- Choose one of 2 options.Male — 0 points · Female — 1 point (sex category)
- Congestive heart failure
- 1 point.defaults to off
- Hypertension
- 1 point.defaults to on
- Diabetes mellitus
- 1 point.defaults to off
- Previous stroke, TIA or thromboembolism
- 2 points. Includes peripheral arterial embolism and pulmonary embolism.defaults to off
- Vascular disease
- 1 point. Myocardial infarction, peripheral artery disease or aortic plaque.defaults to off
What you get back
- CHA₂DS₂-VASc scoremain answer
- Out of a maximum of 9.
- CHA₂DS₂-VA score
- The same score without the sex category, as used in the 2024 ESC guideline. Maximum 8.
- Thromboembolic events per 100 person-years
- At this score, in untreated patients in the Danish cohort — roughly, events per 100 patients per year.
- 95% confidence interval for that rate
- Risk band used in that cohort
- What NICE recommends at this score
What this assumes
- This is an estimate for education. It does not diagnose anything and does not replace clinical judgement.
- Scoring follows the definition stated in Olesen et al., BMJ 2011: 1 point each for heart failure, hypertension, diabetes, vascular disease, age 65-74 and female sex; 2 points each for previous thromboembolism and age 75 or over.
- Event rates are hospital admission and death due to thromboembolism at one year in 73,538 Danish patients with non-valvular atrial fibrillation not receiving a vitamin K antagonist or heparin, followed from 1997. They are population rates from a cohort predating direct-acting oral anticoagulants.
- Anticoagulation thresholds quoted are NICE NG196's; other guidelines set them differently, and the 2024 ESC guideline uses the sex-free CHA₂DS₂-VA score.
- The score applies to non-valvular atrial fibrillation and does not cover moderate-to-severe mitral stenosis or mechanical heart valves.
- It estimates thromboembolic risk only and says nothing about bleeding risk.
About this calculator
This is an estimate for education. It does not diagnose anything and does not replace clinical judgement. Whether to anticoagulate someone with atrial fibrillation is a decision made with a clinician, weighing this score against bleeding risk and against what matters to the patient.
What the score does
Atrial fibrillation raises the risk of ischaemic stroke, but not equally in everyone. CHA₂DS₂-VASc sorts patients by how many of seven clinical features they carry, with two of them — prior stroke or thromboembolism, and age 75 or over — worth two points each. The maximum is 9.
The scoring used here is the one stated in the Danish nationwide validation study: one point each for heart failure, hypertension, diabetes, vascular disease, age 65-74 and female sex, and two points each for previous thromboembolism and age 75 or over.
Annual risk by score
The table under the results gives event rates from that study — 73,538 patients with non-valvular atrial fibrillation who were not taking a vitamin K antagonist or heparin, so the rates describe untreated risk. At one year of follow-up:
- Score 0 — 0.78 events per 100 person-years
- Score 1 — 2.01
- Score 2 — 3.71
- Score 4 — 9.27
- Score 6 — 19.74
Three caveats attach to those numbers and all three matter. They describe a Danish cohort followed from 1997, so they predate direct-acting oral anticoagulants and reflect background stroke rates that have since fallen. They are population rates, not a prediction for one person. And at the top of the range the confidence intervals are enormous — only 46 untreated patients scored 9, giving an interval from 10.6 to 52.6.
Thresholds
NICE recommends offering a direct-acting oral anticoagulant at a score of 2 or above, taking bleeding risk into account, and considering one for men with a score of 1. The evidence NICE reviewed put the sensitivity of a 2-or-more threshold at 0.92 with a specificity of 0.23 — deliberately lopsided, because the committee judged the harm of missing someone who goes on to have a stroke as greater than the harm of anticoagulating someone who would not have.
Note what the score-of-1 recommendation says: men. A woman under 65 with no other risk factor scores 1 on sex category alone, and that is not the same clinical situation.
The sex category is going away
Female sex has come to be seen as a risk modifier — it amplifies the effect of other risk factors — rather than an independent risk factor in its own right. The 2024 ESC atrial fibrillation guideline responded by dropping it, producing CHA₂DS₂-VA: the same score without the sex category, maximum 8. Both are shown here, because which one your local guideline uses determines which thresholds apply.
What it does not tell you
Nothing about bleeding. NICE is explicit that a bleeding-risk tool should not be used as a cut-off for who gets anticoagulated, but to quantify absolute bleeding risk so it can be discussed properly; it recommends ORBIT for that, on the grounds that it predicts absolute risk more accurately than HAS-BLED or ATRIA. The score also applies only to non-valvular atrial fibrillation — moderate-to-severe mitral stenosis and mechanical valves are managed differently. And risk is not static: it should be reassessed as someone ages and as conditions accumulate.
Frequently asked questions
▸How is CHA2DS2-VASc scored?
One point each for heart failure, hypertension, diabetes, vascular disease, age 65-74 and female sex; two points each for previous stroke, TIA or thromboembolism and for age 75 or over. Maximum 9.
▸What is the annual stroke risk for each score?
In 73,538 untreated Danish patients at one year: 0.78 events per 100 person-years at score 0, 2.01 at 1, 3.71 at 2, 5.92 at 3, 9.27 at 4 and 15.26 at 5. Those rates predate direct-acting oral anticoagulants.
▸At what score is anticoagulation recommended?
NICE recommends offering a direct-acting oral anticoagulant at a score of 2 or above and considering one for men with a score of 1, in both cases taking bleeding risk into account. It remains a shared decision.
▸What is CHA2DS2-VA?
The same score with the sex category removed, maximum 8. The 2024 ESC atrial fibrillation guideline adopted it because female sex is now regarded as a risk modifier rather than an independent risk factor.
▸Does the score account for bleeding risk?
No. It measures only thromboembolic risk. NICE recommends assessing bleeding separately with the ORBIT score, and says a bleeding score should inform the conversation rather than act as a cut-off.
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