Built and fact-checked by the DocNectar team — see our editorial standards
Key Features
Instant Calculation
Get accurate results in real time with our optimized algorithm.
Mobile Friendly
Fully responsive design. Works on all devices & screen sizes.
Privacy Focused
Your data stays on your device. We don't store any inputs.
100% Free
No hidden costs. This tool is completely free forever.
The Ankle-Brachial Index (ABI) is a simple ratio: the higher of the two ankle systolic blood pressures divided by the higher of the two arm systolic blood pressures, per the AHA's published measurement guidance. This calculator is for general reference and educational purposes only — it is not a medical diagnosis. Consult a doctor for actual peripheral artery disease assessment.
How it works
Enter the higher ankle systolic pressure and the higher arm systolic pressure (both mmHg). The tool divides the two and classifies the result against published bands.
- Enter higher ankle systolic pressure (mmHg).
- Enter higher arm systolic pressure (mmHg).
- Click Calculate to see your results.
Examples
Ankle systolic 130, arm systolic 120 (mmHg)
ABI = 130/120 = 1.08 — normal.
Who should use it
- Screening for peripheral artery disease risk.
- Tracking vascular health trends over time alongside a doctor.
Industry applications
- Vascular medicine and cardiology reference
- Primary care screening
Advantages
- Non-invasive, requiring only a blood pressure cuff and Doppler (or automated device).
- Backed by decades of published vascular research.
Limitations
- Less reliable in patients with heavily calcified, non-compressible arteries (common in some patients with diabetes).
- A screening tool, not a stand-alone diagnosis.
Common mistakes to avoid
- Using a single ankle or arm reading instead of the higher of the two sides as the published method specifies.
- Measuring pressures inconsistently (e.g. different cuff positions or patient positioning) between visits.
Best practices
- Measure blood pressure in both arms and both ankles, then use the higher reading from each side as specified in the AHA guidance.
Tips
- If your ABI is outside the normal range, discuss further vascular testing with a doctor.