Percentage calculator
Answer the three most common percentage questions: what is X % of a number, what % is one number of another, and how much has something gone up or down.
Percentage calculator: what it is and how it works
A percentage expresses an amount as a part of one hundred. Saying 20 % of students passed with honours means 20 out of every 100 did. Percentages are everywhere: discounts, taxes, interest, surveys, statistics and price rises.
This calculator handles the three most common cases. First, a percentage of a number: multiply the number by the percentage and divide by 100. Second, what percentage a part is of a total: divide the part by the total and multiply by 100. Third, the percentage change between an original and a new value, showing how much something has risen or fallen in proportion.
How to use it
- Choose what you want to calculate from the menu.
- Enter the two values requested.
- Read the result and the extra details.
X % of Y = Y × X ÷ 100 · % = part ÷ total × 100 · Change = (new − original) ÷ original × 100Worked example
20 % of 150 is 30. 30 out of 150 is 20 %. If a price goes from 80 to 100, it has risen 25 %; if it falls from 100 to 80, it has dropped 20 %.
Frequently asked questions
How do I work out a percentage of a number?
Multiply the number by the percentage and divide by 100. For example, 15 % of 60 is 60 × 15 ÷ 100 = 9.
How do I find what percentage one number is of another?
Divide the part by the total and multiply by 100. 45 out of 180 is 45 ÷ 180 × 100 = 25 %.
Why doesn’t a 25 % rise followed by a 25 % fall cancel out?
Because the second percentage applies to a different amount. 100 + 25 % = 125, and 125 − 25 % = 93.75.
What is the difference between percentage points and percent?
If a rate goes from 2 % to 3 %, it rises by 1 percentage point, but proportionally it has risen by 50 %.