Percentage Change Calculator
The Percentage Change Calculator measures how much a value increased or decreased from its starting point, as a percent — useful for prices, salaries, revenue and budgets.
What this means
Percentage change compares a new value to its starting value: how much did it move, relative to where it started? A rise from $50 to $60 is a 20% increase.
How we calculate it
Formula
Change % = (new − old) / |old| × 100.Worked example
A salary growing from $50,000 to $55,000:
- 1Change % = (55,000 − 50,000) / 50,000 × 100
- 2Change % = 10% increase
Important assumptions
- The old value is the starting reference point.
- Negative results indicate a decrease.
Frequently asked questions
What if the old value is zero?
Percentage change is undefined from zero — you can't divide by zero. In that case, compare absolute amounts instead.
How is this different from percentage difference?
Percentage change uses the starting value as the base. Percentage difference typically uses the average of the two values as the base. Both answer different questions.