Health

Ankle-Brachial Index (ABI) Calculator

Screen for peripheral arterial disease using blood pressure ratios.

Right Arm Systolic BP (mmHg)

Left Arm Systolic BP (mmHg)

Right Ankle Systolic BP (mmHg)

Left Ankle Systolic BP (mmHg)

Right ABI—

Left ABI—

Lowest ABI—

Interpretation—

Formula:
ABI = Highest Ankle Systolic BP / Highest Arm Systolic BP
Normal: 1.0 – 1.4 | Borderline: 0.91 – 0.99 | PAD: ≤ 0.90

About the ABI

The Ankle-Brachial Index is a quick, non-invasive screening test for peripheral arterial disease. An ABI ≤ 0.90 has 95% sensitivity and 99% specificity for PAD confirmed by angiography. Values above 1.4 suggest non-compressible calcified arteries (common in diabetes) and are unreliable.