Percentage Increase Calculator
Calculate the percentage increase or decrease from an old value to a new value, with the difference and the formula.
Percentage increase formula
Percentage increase = (New value − Original value) ÷ Original value × 100
A price rises from $80 to $100. The increase is $20, and $20 ÷ $80 = 0.25, so the price went up 25%.
If the result is negative, it is a percentage decrease. A fall from $100 to $80 is (80 − 100) ÷ 100 = −20%, a 20% decrease.
Why up 25% and down 20% cancel out
Percentage changes are measured from the starting value, which changes direction to direction. That is why a 50% loss on an investment needs a 100% gain to recover, and why a 10% raise followed by a 10% pay cut leaves you 1% worse off.
Common uses
- Prices and inflation: how much more something costs than last year.
- Salary: the percentage raise between two salaries (see the raise calculator).
- Business: month-over-month or year-over-year growth in sales or traffic.
- Investments: the return on a stock or fund between two dates.
Percentage increase vs percentage points
When the values are already percentages, say whether you mean the relative change or the simple difference. An interest rate rising from 4% to 5% is a 25% increase but a 1 percentage point rise.
Frequently asked questions
How do I calculate a percentage increase?
Subtract the original value from the new value, divide by the original value and multiply by 100.
How do I calculate a percentage decrease?
Use the same formula. A negative result is a decrease; for example 50 to 40 is −20%.
What is a 100% increase?
A 100% increase means the value has doubled. A 200% increase means it has tripled.
Last reviewed Oct 20, 2026. Results are estimates; check important decisions with a qualified professional.