CHA₂DS₂-VASc Calculator
Stroke risk in atrial fibrillation.
About this tool
CHA₂DS₂-VASc estimates the annual risk of stroke for people with atrial fibrillation and informs the decision about long-term oral anticoagulation. It's the standard tool used in ESC, ACC/AHA, and NICE guidelines.
Use this calculator only if you have a confirmed diagnosis of atrial fibrillation. Pair it with the HAS-BLED score for a balanced view of stroke vs bleeding risk.
Source: Lip GYH et al., Chest 2010.
Frequently asked questions
What does the '₂' mean in CHA₂DS₂-VASc?
It marks the components worth 2 points each: Age ≥75 (A₂) and prior Stroke/TIA (S₂). All other items score 1 point.
Why does being female add a point?
Female sex is a risk modifier — it raises stroke risk when other risk factors are present, but a score of 1 from female sex alone is not an indication for anticoagulation.
Does this apply to all heart rhythm problems?
No — it's validated specifically for atrial fibrillation (and atrial flutter), not other arrhythmias.
⚕️ Educational only — not a substitute for professional medical advice, diagnosis, or treatment. In an emergency call your local emergency services.