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Percentage Calculator
Three answers in one place: what is X% of Y, X is what percent of Y, and X is Y% of what number. Type in any box and the result updates.
What is X% of Y?
X is what percent of Y?
X is Y% of what number?
The three formulas
| Question | Formula | Example |
|---|---|---|
| X% of Y | X / 100 x Y | 15% of 80 = 12 |
| X is what % of Y | X / Y x 100 | 12 is 15% of 80 |
| X is Y% of what | X / (Y / 100) | 12 is 15% of 80 |
A quick way to do it in your head
Ten percent of a number is the number with the decimal point moved one place left: 10% of 80 is 8. Five percent is half of that, 4. So 15% of 80 is 8 + 4 = 12. One percent is the decimal point moved two places.
To work out a rise or a fall, use the percentage increase and percentage decrease calculators. The guide to percentage formulas covers the common mistakes.
Frequently asked questions
How do I calculate X% of a number?
Divide the percentage by 100 and multiply by the number. 15% of 80 is 15 / 100 x 80 = 12.
How do I find what percent one number is of another?
Divide the first number by the second and multiply by 100. 12 is 12 / 80 x 100 = 15% of 80.
How do I find the whole number when I know a part and the percentage?
Divide the part by the percentage as a decimal. If 12 is 15% of a number, the number is 12 / 0.15 = 80.
How do I calculate a percentage of a percentage?
Multiply them as decimals. 20% of 50% is 0.20 x 0.50 = 0.10, which is 10%. Use the first calculator and enter 20 as the percentage and 50 as the number.
How do I turn a percentage into a decimal?
Divide by 100, which moves the decimal point two places left. 15% is 0.15, and 7.5% is 0.075.