Formula
X% of Y = (X ÷ 100) × YX is what % of Y = (X ÷ Y) × 100Whole = X ÷ (Y ÷ 100)
- X, Y — the numbers you enter
- Percent literally means “per hundred”, so dividing by 100 turns a percentage into a plain multiplier.
Turn the percentage into a decimal by dividing by 100, then multiply. To go the other way, divide the part by the total and multiply by 100.
Worked examples
15% of 200
- What do you want to find?
- What is X% of Y?
- Percentage (X)
- 15 %
- Number (Y)
- 200
Result
30
As a fraction of the whole: 0.15
30 out of 200
- What do you want to find?
- X is what percent of Y?
- Part (X)
- 30
- Total (Y)
- 200
Percentage
15%
As a decimal: 0.15
30 is 15% of what?
- What do you want to find?
- X is Y% of what number?
- Part (X)
- 30
- Percentage (Y)
- 15 %
The whole is
200
How it works
To find a percentage of a number, divide the percentage by 100 and multiply. 15% of 200 is 0.15 × 200 = 30. To find what percentage one number is of another, divide the part by the total and multiply by 100: 30 out of 200 is 30 ÷ 200 × 100 = 15%.
If you know a part and the percentage it represents, divide the part by the percentage (as a decimal) to get the whole: 30 is 15% of 30 ÷ 0.15 = 200.
To compare a value before and after a change use Percentage Change Calculator; to add or remove a percentage from a price see Percentage Increase Calculator and Percentage Decrease Calculator.
Assumptions and limits
- Results are shown to at most 6 decimal places (percentages to 4) and trailing zeros are dropped.
- Negative numbers are allowed and follow the same formulas.