Percentage Change Calculator
Calculate the percentage increase or decrease between two values. Free, fast and easy to use.
How it works
Compare an original value with a new one to see how much it changed in percent. A positive result is an increase, a negative result is a decrease. Use it for prices, salaries, website traffic or any before-and-after comparison.
Formula
(New − Original) / |Original| × 100
Worked examples
- Original value: 80 · New value: 100 → Change: 25%
- Original value: 1200 · New value: 900 → Change: -25%
- Original value: 2.5 · New value: 3.1 → Change: 24%
Calculations run locally in your browser. Results are for information only — for engineering, electrical or financial decisions, verify the assumptions and applicable standards.
Frequently asked questions
How is percentage change calculated?
Subtract the original value from the new value, divide by the original value and multiply by 100. From 80 to 100 is (100 − 80) / 80 × 100 = 25 %.
Why is a 50 % drop not undone by a 50 % rise?
Because the percentages are taken from different bases. 100 falling by 50 % gives 50, and 50 rising by 50 % gives only 75; you would need a 100 % rise to get back to 100.