About this tool
Why it exists.
Percentage change tells you how much a value has grown or shrunk compared with where it started. It is used for prices, salaries, website traffic, savings, sales and almost anything that moves over time. A single number such as +25% is easier to compare than two raw figures.
Enter the starting value and the ending value. The calculator subtracts one from the other, divides by the starting value and multiplies by 100. A positive result is an increase and a negative result is a decrease. The formula is shown under the result so you can check it by hand.
How to use it.
- Enter the starting value.
- Enter the ending value.
- Read the percentage change, the difference and the direction.
Good questions.
Why is a rise of 25% not reversed by a fall of 25%?
The two changes use different starting values. A rise from 80 to 100 is +25%. A fall from 100 back to 80 is only −20%, because the change is now measured against 100.
What is the difference between percent and percentage points?
If a rate moves from 4% to 6%, it rose by 2 percentage points, which is a 50% increase in the rate itself. Use percentage points for the raw gap and percent change for the relative gap.
Why can the starting value not be zero?
The formula divides by the starting value, and dividing by zero is undefined. If something grew from nothing, the percentage change cannot be calculated.