CHA₂DS₂-VASc Calculator
A Scoring Scheme Named After Its Own Checklist
CHA²DS²-VASc is an acronym that doubles as its own scoring rubric: each letter is a risk factor, and the superscript twos mark the two factors worth double points. Built as a refinement of the earlier CHADS² score, its particular strength is at the low end — it is markedly better at identifying people with atrial fibrillation who are genuinely at low stroke risk, which is a harder and arguably more useful discrimination than flagging the obviously high-risk. This calculator performs the standard point arithmetic and looks up the corresponding published risk figure.
The Scoring
H — Hypertension +1
A² — Age 75 or over +2 (age 65–74 scores +1)
D — Diabetes mellitus +1
S² — Prior stroke / TIA / thromboembolism +2
V — Vascular disease (MI, PAD, aortic plaque) +1
A — Age 65–74 +1
Sc — Sex category (female) +1
Total = sum of all applicable points (capped at 9)
The two double-weighted items share a logic: advanced age and a stroke that has already happened are the strongest signals in the set. Prior stroke in particular is the closest thing the score has to a settled predictor — the best guide to a future event is often a past one.
Published Annual Stroke Risk by Score
This calculator maps the computed score to the risk figures below, adapted from the widely-cited Friberg et al. 2012 Swedish registry validation cohort:
| Score | Approximate annual stroke risk |
|---|---|
| 0 | 0.0% |
| 1 | 1.3% |
| 2 | 2.2% |
| 3 | 3.2% |
| 4 | 4.0% |
| 5 | 6.7% |
| 6 | 9.8% |
| 7 | 9.6% |
| 8 | 6.7% |
| 9 | 15.2% |
The figures are not perfectly monotonic — scores of 7, 8 and 9 were represented by small numbers of patients in the validation cohort, so those percentages carry wide uncertainty. This is registry data, not a smooth model, and the table is reproduced as published rather than tidied.
Why Age Appears Twice
Age is the only factor in the acronym occupying two separate letters, and this calculator handles it as a single graded band rather than two independent checks: 75 and over scores +2, 65 to 74 scores +1, and under 65 scores nothing. The scheme is stepped rather than continuous, which means a 74th birthday and a 75th birthday are separated by a full point — a reminder that the score is a clinical simplification of a smooth underlying relationship.
Where the Score Appears
- Atrial fibrillation guidelines — major cardiology societies reference it directly when framing anticoagulation discussion.
- Shared decision-making — it gives patients and clinicians a common number to reason about together.
- Risk communication research — the score is a standard example of how graded point systems translate multiple factors into one figure.
How to Use This Calculator
- Enter Age (years) — the calculator assigns +2, +1 or +0 automatically from the bands above.
- Select Sex; female adds +1 under the Sc criterion.
- Tick each applicable checkbox: congestive heart failure, hypertension, diabetes, prior stroke or TIA, and vascular disease.
- Select Calculate. The result shows the total score with a full line-by-line breakdown of which criteria contributed, plus the published risk figure for that score.
Related Calculations
For a different view of cardiovascular risk factors, see the Heart Attack Risk Calculator, or explore another point-based clinical scoring scheme with the Wells Score Calculator.