Percentage calculators
Percentages are where confident arithmetic goes wrong, because “a percentage of what” is the question the notation hides. An increase and its reversal are not the same size, successive discounts do not add up, and the difference between two percentages is not itself a percentage. Each of these names its base.
Percentage CalculatorWhat one number is as a percentage of another, and what that percentage of a number comes to. The plainest arithmetic on the site, done with the working shown.Percentage Increase CalculatorIncrease a number by a percentage. Note that reversing this needs division, not subtraction. The reverse-percentage calculator handles that.Percentage Decrease CalculatorDecrease a number by a percentage, with the amount removed shown separately.Percentage Change CalculatorPercentage change between two values, in either direction, with the absolute change shown alongside. Handles a negative starting value, which most calculators get wrong.Percentage Difference CalculatorPercentage difference and percentage change, which are different measures constantly used interchangeably. Difference is symmetric; change depends on which value you started from.Percent of a Number CalculatorA percentage of a number, with the increase and decrease shown alongside. Finding a percentage and adding one are different questions and the page answers both.What Percent of X is Y CalculatorWhat percentage one number is of another. The most common percentage question and the one phrased most awkwardly.Reverse Percentage CalculatorWork backwards from a value that has already had a percentage applied. Division, not subtraction. Taking 12% off 1120 gives 985.60, but the original was 1000.