Ankle Brachial Index (ABI) Calculator
The Ankle-Brachial Index (ABI) is a quick, non-invasive way to check for peripheral artery disease (PAD). This calculator compares the blood pressure measured at your ankle with the blood pressure measured at your arm.
Arm Systolic Pressure
Ankle Systolic Pressure
Understanding the Ankle Brachial Index (ABI)
The Ankle-Brachial Index (ABI) is a simple, non-invasive medical test used to diagnose Peripheral Artery Disease (PAD). PAD is a condition where the arteries in your legs or arms are narrowed or blocked, which can lead to a higher risk of heart attack, stroke, and poor circulation.
The ABI Formula
ABI = (Highest Systolic Pressure in Ankle) / (Highest Systolic Pressure in Both Arms)
How to Interpret Your Results
Clinicians typically use the following ranges to categorize the health of the lower extremity arteries:
- 1.00 – 1.40: Normal. Your blood flow is likely healthy.
- 0.91 – 0.99: Borderline. You may be at risk for PAD.
- 0.41 – 0.90: Mild to Moderate PAD. Indicates narrowed arteries.
- 0.00 – 0.40: Severe PAD. Significant blockage is present.
- Above 1.40: Non-compressible. May indicate calcified or rigid vessels, often seen in diabetes or chronic kidney disease.
Example Calculation
Imagine a patient has a systolic arm pressure of 120 mmHg in the right arm and 124 mmHg in the left. The highest arm pressure is 124. If their right ankle pressure is 130 mmHg, the right ABI is:
130 / 124 = 1.05 (Normal)
If the left ankle pressure is 80 mmHg, the left ABI is:
80 / 124 = 0.64 (Mild to Moderate PAD)
Disclaimer: This calculator is for educational purposes only and does not substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician.