Percent Difference

Percentage difference measures the difference between two values relative to their average. Unlike percentage change (which has a direction), percentage difference treats both values symmetrically and is used when neither value is a "baseline"

The calculator uses the standard published formula for percent difference. Results are accurate to the precision of the inputs you provide. For financial, medical, or legal decisions, always verify with a qualified professional.

This calculator works with inches. You can enter values in the units shown — the calculator handles all conversions internally.

The core formula is: Percentage difference = |V1 − V2| / ((V1 + V2) / 2) × 100. Each step in the calculation is shown so you can verify the result manually.