How it is calculated
Change % = (new − old) ÷ |old| × 100A positive result is an increase; a negative result a decrease. Note that +50% then −50% does not return you to the start.
Worked example
A salary rising from 8,000 to 8,600: increase = 600 ÷ 8,000 × 100 = 7.5%. A price falling from 250 to 200: a 20% decrease.
Frequently asked questions
Percentage change vs percent difference?
Change compares with the old value; percent difference compares with the average of both and is used when there is no “old” value.
Average yearly increase over several years?
Use the compound annual growth rate in the ROI calculator.
What if the old value is zero?
A percentage change from zero is mathematically undefined.