How to calculate % change
% change = (New − Original) ÷ |Original| × 100
Worked example. Percent increase: 25%.
Example inputs — Original value: 80; New value: 100. Starting values are illustrative.
From George Guju, founder of Calculyn · Educational calculator guidance, not professional advice.
How it works
Percent change compares the difference between two values to the original value.
Assumptions & limitations
- Results are rounded for display.
Formula and assumptions reviewed October 2026 by the Calculyn team. How we build our calculators
Frequently asked questions
Why isn't a 20% drop reversed by a 20% rise?
Because each percentage is taken from a different starting value.