Percentage Change Calculator
Compare two numbers to find the percentage increase or decrease between them.
Increase and decrease
Percentage change is (new − old) / |old| × 100. A positive result is an increase; a negative one is a decrease. It is the right tool for price changes, growth rates, and before/after comparisons.
A common trap
A 50% drop followed by a 50% rise does not return you to the start — 100 → 50 → 75. Percentage changes are relative to the value at each step, so gains and losses of the same percentage do not cancel out.
Frequently asked questions
Why is a 50% loss not offset by a 50% gain?
Because each percentage is applied to a different base. After a 50% loss you need a 100% gain to break even.