Percentage Calculator
Three everyday percentage sums, with the working shown. Results update as you type.
What is X% of Y?
30
20 ÷ 100 × 150 = 30
X is what percent of Y?
25%
30 ÷ 120 × 100 = 25%
Percentage increase or decrease
+25% increase
(100 − 80) ÷ 80 × 100 = 25%
Percentage formulas
- X% of Y: X ÷ 100 × Y
- X as a percent of Y: X ÷ Y × 100
- Percentage change from X to Y: (Y − X) ÷ X × 100
Everyday uses
Work out sale prices and discounts, tax and service charges, test scores, pay rises, price increases and how much a figure has grown. For tips at a restaurant, the tip calculator also splits the bill.
Frequently asked questions
How do I calculate a percentage of a number?
Divide the percentage by 100 and multiply by the number. For example, 20% of 150 is 20 ÷ 100 × 150 = 30.
How do I work out what percent one number is of another?
Divide the part by the whole and multiply by 100. For example, 30 out of 120 is 30 ÷ 120 × 100 = 25%.
How do I calculate percentage increase or decrease?
Subtract the old value from the new one, divide by the old value and multiply by 100. Going from 80 to 100 is (100 − 80) ÷ 80 × 100 = 25% more. A negative result is a decrease.
How do I work out a discount?
Use the first calculator to find the discount: 25% of 60 is 15, so the sale price is 60 − 15 = 45. To find the discount you got, use the third: from 60 to 45 is a 25% decrease.
Why isn't a 50% rise followed by a 50% fall back to the start?
Because each percentage is of a different amount. 100 plus 50% is 150, but 50% of 150 is 75, so the result is 75, a 25% fall overall.