Percentage change tells you how much a value has grown or shrunk relative to where it started. Use it for prices, salaries, website traffic, grades or any before-and-after comparison.
How to use this calculator
Enter the original value and the new value. A positive result is an increase and a negative result is a decrease. The absolute change is shown too.
The formula
Percentage change = (new value - original value) / |original value| x 100. Dividing by the absolute value of the original keeps the sign meaningful when the starting number is negative.
Worked examples
Going from 80 to 100 is a change of +20, which is +25% of 80. Going from 100 back to 80 is -20, which is -20% of 100. The two are not symmetric, because each percentage is measured against a different starting value. This is why a 50% drop needs a 100% gain to recover.
Frequently asked questions
Is percentage change the same as percentage points? No. If a rate moves from 10% to 12%, it rose 2 percentage points but 20% in relative terms.
What if the original value is zero? The percentage change is undefined, so the calculator shows 0.