Percentage difference vs. percentage change

Choose the correct formula depending on whether values have a meaningful starting point or are peers being compared.

By Calculadoras.Tools Published April 15, 2026 5 min read

Percentage change compares a new value with a meaningful original value:

percentage change = (new - original) / original x 100

Moving from 80 to 100 is a 25% increase.

Percentage difference compares two peer measurements when neither is naturally the baseline:

percentage difference = |A - B| / ((A + B) / 2) x 100

For 80 and 100, the absolute difference is 20 and their average is 90, so the percentage difference is 22.22%.

Use change for prices over time, growth from a baseline or before-and-after measurements. Use difference for two laboratories, two estimates or two values of equal status. The formulas are not interchangeable because their denominators answer different questions.

The sign of percentage change indicates direction; percentage difference is normally nonnegative. Use the percentage calculator for change and keep the selected baseline explicit.