Percentage Change Calculator
Calculate percentage increase/decrease, reverse changes, or compounding multi-step percentage changes.
Calculate the percentage increase or decrease from one value to another.
Formula & Steps
Formula: ((New - Old) / |Old|) × 100
Steps: ((150 - 120) / |120|) × 100 = (30 / 120) × 100 = 25%
Understanding Percentage Change and Compounding
Percentage change measures the relative growth or shrinkage between an initial value and a final value. For a single step, it is calculated as ((New − Old) ÷ |Old|) × 100.
When dealing with multiple sequential percentage changes, they compound rather than add up linearly. For example, a +10% increase followed by a -10% decrease does not bring you back to 100% — it results in 99% of the starting value (a net -1% change). This calculator handles the compounding math automatically.
Private & free — this tool runs entirely in your browser.