Percentage change calculator
Calculate percentage increase, decrease, difference and reverse percentages.
Percentage change
A difference of 25.
Calculate the percentage increase or decrease between two numbers, or reverse a percentage change. Results update as you type and stay in your browser.
Change compared with the starting value
Percentage change is (new − old) ÷ |old| × 100. Using the starting value as the denominator makes increases and decreases comparable.
Zero needs special treatment
A percentage change from zero is undefined, so the calculator shows the absolute difference instead.
Frequently asked questions
Can percentage change exceed 100%?
Yes. Going from 10 to 25 is a 150% increase.
Why are opposite changes not symmetrical?
A 50% fall halves a value; returning to the original then requires a 100% increase.
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