How percentage change works
Compare a new value with a positive starting value.
Formula and convention
Percentage change = (new - original) / original x 100.A worked example
Moving from 80 to 100 is a 25% increase. Moving back from 100 to 80 is a 20% decrease.
Scope and precision
The original value must be positive. Percentages are relative to the starting value, so increases and decreases are not symmetric.
Displayed results may be rounded. Inputs are processed locally and are not stored by this site. Keep the original values if you need to reproduce the result.
Why might another tool give a different result?
Compare unit definitions, rounding, period assumptions, and input values. This page states the convention used by this calculator.