How to calculate percentage change?

Percentage change calculates the degree to which a number has increased or decreased over time. Subtract the old number from the new number, divide the result by the old number (base value), and multiply by 100. Positive results mean an increase; negative results mean a decrease.

Formula

Change % = ((New Value − Old Value) ÷ Old Value) × 100

Worked Example

Value goes from 200 to 150.

1. Difference: 150 − 200 = -50
2. Ratio: -50 ÷ 200 = -0.25
3. Percent: -0.25 × 100 = -25%

Result: The value decreased by 25%.