Percentage Change Calculator
Enter an initial value and a final value to find the percentage increase or decrease between them.
What is percentage change?
Percentage change measures how much a value has increased or decreased relative to its starting point, expressed as a percentage. It’s used everywhere from tracking price changes and salary raises to comparing test scores or business metrics.
The formula
The standard formula is: Percentage Change = ((Final Value − Initial Value) ÷ |Initial Value|) × 100. A positive result means an increase, while a negative result means a decrease. Using the absolute value of the initial value in the denominator keeps the sign of the result meaningful even when the initial value is negative.
Note: if the initial value is zero, percentage change is mathematically undefined (you can’t divide by zero), so this calculator will show 0% in that edge case rather than an error. This tool is for general educational and reference purposes.