Percentage Calculator

Worked example

20% of 50 is 10, because 20 ÷ 100 × 50 = 10. Enter 20 and 50 to see it, or enter 20 and 10 to find the number.

How it works

The three boxes are linked by one relationship: Result = Percentage ÷ 100 × Number. Fill in any two and the third is worked out. With a percentage and a number it finds the result: 20% of 50 is 10. With a result and a number it finds the percentage: 10 is 20% of 50. With a result and a percentage it finds the number: 10 is 20% of 50. When you type in the calculated box, it becomes one of your values and the box you edited longest ago becomes the calculated one. Clear a box to have it worked out. Finding the percentage needs a number other than 0, and finding the number needs a percentage other than 0, since dividing by zero has no answer.

A result written as a plain number is exact. A result starting with “≈” has been rounded to 10 significant figures, because its exact decimal never ends or is too long to read comfortably. When an exact value is long, its full digits are shown underneath. The calculation itself is never rounded: only the display is.