What does CHADS2 stand for?

C = Congestive heart failure (1 pt), H = Hypertension (1 pt), A = Age 75 or older (1 pt), D = Diabetes mellitus (1 pt), S2 = prior Stroke or TIA (2 pts). The "2" in S2 indicates double weighting for prior stroke or TIA.

What is the maximum CHADS2 score?

The maximum score is 6. Prior stroke or TIA carries 2 points; all other factors carry 1 point each. A score of 6 corresponds to an estimated annual stroke risk of about 18.2%.

What is the difference between CHADS2 and CHA2DS2-VASc?

CHA2DS2-VASc is the newer, more comprehensive score. It adds vascular disease, age 65-74, and female sex as additional risk factors, making it better at identifying truly low-risk patients. Most current guidelines recommend CHA2DS2-VASc over the original CHADS2 score.

Does a score of 0 mean no anticoagulation is needed?

A score of 0 indicates low risk (estimated 1.9% annual stroke risk). Current guidelines generally suggest aspirin or no antithrombotic therapy for these patients, but the decision must be individualized by a qualified clinician.

Does this tool give medical advice?

No. This calculator is for educational and informational purposes only. All clinical decisions about anticoagulation must be made by a qualified healthcare professional, considering the individual patient's full clinical picture and bleeding risk.

CHADS2 Score Calculator

Name: CHADS2 Score Calculator
Availability: InStock
Author: Nham Vu

Calculate the CHADS2 score to estimate annual stroke risk in non-valvular atrial fibrillation patients.

Patient Risk Factors

Check every criterion that applies. Score updates instantly.

C — Congestive Heart Failure Signs or symptoms of heart failure, or reduced LVEF (< 40%)

H — Hypertension History of hypertension or currently on antihypertensive treatment

A — Age ≥ 75 Years Patient is 75 years of age or older

D — Diabetes Mellitus Fasting glucose > 125 mg/dL or on hypoglycemic treatment

S2 — Prior Stroke or TIA History of any ischemic stroke or transient ischemic attack (double weight)

Note: The CHA₂DS₂-VASc score is the more modern and preferred tool in current guidelines. It includes additional risk factors (vascular disease, age 65–74, female sex) and provides better discrimination of truly low-risk patients. Consider using the CHA₂DS₂-VASc calculator for a more comprehensive assessment.

CHADS2 Score

out of 6 possible points

Annual Stroke Risk by Score

Guideline Recommendation

Select risk factors to see a recommendation.

For informational purposes only. All clinical decisions must be made by a qualified healthcare professional.

Medical Disclaimer: This tool is intended for educational and informational purposes only. It does not constitute medical advice, diagnosis, or treatment. Always consult a qualified healthcare professional before making any clinical decisions.

Summary

Calculate the CHADS2 score to estimate annual stroke risk in non-valvular atrial fibrillation patients.

How it works

Select each risk factor that applies to the patient.
The score updates automatically as you toggle each factor.
Review the total score and the corresponding estimated annual stroke risk.
Use the recommendation panel to understand guideline-based anticoagulation guidance.
Note that CHA2DS2-VASc is the preferred modern score for more granular risk stratification.

Use cases

Quickly assess stroke risk for patients with atrial fibrillation.
Support clinical decision-making about anticoagulation therapy.
Educate medical students and nursing staff on CHADS2 scoring.
Cross-check manual scoring at the bedside or during telehealth visits.
Use as a baseline before applying the more detailed CHA2DS2-VASc score.
Document stroke risk stratification in clinical notes.

Frequently Asked Questions

Last updated: 2026-06-09 · Reviewed by Nham Vu