Percentage Calculator

Three calculators in one: find a percentage of a number, work out what percent one value is of another, and measure the percent increase or decrease between two numbers.

Percentage (X)Of value (Y)

Enter both values to see the result.

What this tool does

It handles the three percentage questions that come up most. What is X percent of Y, for working out discounts or tips. X is what percent of Y, for turning a part and a whole into a percentage. And percent change from one number to another, for growth, markups, or drops. Switch modes with the tabs and the labels update so you always know which value goes where.

How percent change works

Percent change compares a new value against an original one: subtract the old from the new, divide by the old, and multiply by 100. A positive result is an increase, a negative one is a decrease. So going from 80 to 100 is a 25 percent increase, while 100 down to 80 is a 20 percent decrease. The direction and sign are shown for you so there's no second-guessing.

Everyday uses

Sale prices, tax, tip splits, test scores, commission, and tracking how a number moved over time all come down to one of these three calculations. Rather than remembering which formula to use, pick the question that matches and read off the answer. It all runs locally in your browser.