Percentage change calculator
Compare a starting value with a new value to see how much it went up or down, as a percentage. Use it for price changes, sales growth, weight changes or test score improvements.
- Runs in your browser
- Free, no account needed
- Copy or download the result
Result
Example
80, 100
Change: 25% Difference: 20
How to use the percentage change calculator
- Type the original value and the new value separated by a comma, such as 80, 100.
- Set Maximum decimal places to a whole number from 0 to 12.
- Press Run to see the change and the difference.
- Press Copy result or Download to save it.
How it works
Percentage change = (new - old) / old x 100. A negative result means a decrease.
The result has two lines: Change, as a percentage, and Difference, which is new minus old.
The original value must be greater than zero. A zero or negative starting value is rejected with an error.
The math uses exact fractions, then rounds to your chosen decimal places with halves rounded away from zero.
Enter plain decimal numbers with up to 100 digits each. E notation and % signs are not accepted.
Everything runs in your browser. Your input is not uploaded or stored.
Questions and answers
How do you calculate percentage change?
Subtract the old value from the new value, divide by the old value, and multiply by 100. Going from 80 to 100 is (100 - 80) / 80 x 100 = 25%.
What is the difference between percentage change and percentage points?
Percentage points are the plain difference between two percentages. Going from 10% to 15% is 5 percentage points but a 50% change. Enter 10, 15 here to see Difference 5 and Change 50%.
Why can't the starting value be zero?
Percentage change divides by the starting value, and dividing by zero has no answer. This tool also requires a positive start so a plus or minus sign clearly means an increase or a decrease.
Does a 50% increase undo a 50% decrease?
No. 100 down 50% is 50, and 50 up 50% is only 75. Each change is measured against its own starting value.