Calculadora de Diferença Percentual
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
diferença = |A − B| / ((A + B)/2) × 100
About this calculator
The Percent Difference Calculator computes the relative difference between two values using the average as the reference. Unlike percent change, which uses one value as the base, this formula is symmetric: the result is the same regardless of the order of the numbers. The formula is: difference = |A − B| / ((A + B)/2) × 100. The result is always positive, expressed as a percentage.
This calculator is useful when comparing two values without favoring one as a reference, such as in scientific measurements, comparing prices between stores, or evaluating discrepancies in experiments. For example, comparing two temperature readings or two cost estimates, the percent difference indicates the magnitude of divergence relative to the average.
Cautions: the formula assumes both values are positive. If one value is zero, the calculation is undefined (division by zero). For negative values, interpretation can be problematic. Also, for very small values, the percent difference can be large even if the absolute difference is small. Always consider the context of the data.
Frequently asked questions
What is the difference between percent difference and percent change?
Percent difference uses the average as the reference and is symmetric. Percent change uses one value as the base (usually the initial value) and can be positive or negative, indicating increase or decrease.
Can I use negative values in the calculator?
The standard formula does not handle negative values well, as the average may be zero or near zero, distorting the result. It is recommended to use absolute values or another metric.
What does a result of 0% mean?
It means the two values are equal. The higher the percentage, the greater the relative difference between them.
Does the calculator work if one of the values is zero?
No, because the average would be (A+0)/2, and division by (A/2) is defined, but if both are zero, it is indeterminate. For one zero value, the result will be 200% if the other is nonzero.
When should I use percent difference instead of absolute difference?
Use percent difference when you want to compare the magnitude of the difference relative to the scale of the values, especially when values have different orders of magnitude.