Calculate any percentage in seconds — what is X% of Y, what percent is X of Y, and percentage increase or decrease.
Use the first box for “X% of Y”, the second for “X is what % of Y”, and the third for increase or decrease. Click Calculate after each one.
A percentage is a way of showing a part of a whole as a number out of 100. The word "percent" means "per hundred", so 25 percent means 25 out of every 100. Percentages are used everywhere: in school marks, shop discounts, bank interest, taxes, salary increases, battery levels and sports scores. This free percentage calculator solves the three percentage problems people search for most: finding a percentage of a number, finding what percentage one number is of another, and finding a percentage increase or decrease.
Many people find percentages confusing, but the maths is simple once you know the three formulas below. Students use percentages for exam results, shoppers use them for discounts, business owners use them for profit margins, and workers use them for pay rises. Instead of working it out by hand, enter the numbers in the boxes above and this percentage calculator gives the answer in seconds, with no sign-up and no download.
First, what is 20 percent of 150? Divide 20 by 100 and multiply by 150, which gives 30. Second, 45 marks out of 60 is what percentage? Divide 45 by 60 and multiply by 100, which gives 75 percent. Third, a price rises from 80 to 100. The increase is 20, and 20 divided by 80 times 100 is a 25 percent increase. A shop example: a shirt costs 2,000 and has a 25 percent discount. The discount is 500, so you pay 1,500. Try all three boxes above with your own numbers.
There are three formulas to remember. To find X percent of Y: (X divided by 100) times Y. To find what percentage X is of Y: (X divided by Y) times 100. To find a percentage change: (New value minus Old value) divided by Old value, times 100. A positive answer means an increase and a negative answer means a decrease. For example, if your salary rises from 50,000 to 55,000, the change is (55,000 minus 50,000) divided by 50,000 times 100, which is a 10 percent increase.
Remember that 100 percent is the whole. If you score 100 percent, you got every mark. If a shop gives 100 percent off, the item is free. Check discount claims. A "50 percent off, then 50 percent off again" deal is not free: it is 75 percent off in total. Do not confuse percentage points with percent. A rise from 10 percent to 12 percent is a rise of 2 percentage points, but a 20 percent increase. Use it for exam marks. Divide your marks by the total marks and multiply by 100 to get your percentage. Use it for tips and tax. A 10 percent tip on a 4,000 bill is 400, and a 15 percent tax on 1,000 is 150.
Here are three quick checks you can try in the boxes above. First, what is 40 percent of 2,500? Divide 40 by 100 and multiply by 2,500, which gives 1,000. Second, your salary rises from 60,000 to 66,000. The increase is 6,000, and 6,000 divided by 60,000 times 100 is a 10 percent rise. Third, you scored 18 marks out of 90. Divide 18 by 90 and multiply by 100, which gives 20 percent. The same three formulas solve nearly every percentage problem you will meet.
Adding percentages that should be multiplied. Two discounts of 50 percent do not make 100 percent off: the second discount applies to the already reduced price, so the total is 75 percent off. Confusing percent with percentage points. A rise from 10 percent to 12 percent is 2 percentage points, but a 20 percent increase in the rate. Using the wrong base number. A percentage increase is always divided by the old value, not the new one. Forgetting to divide by 100. The percent sign means "out of 100", so 20 percent of 150 is 20 divided by 100 times 150, which is 30, not 3,000. Rounding too early. Keep full numbers while you calculate and round only the final answer.
Pro Tip: To find 10 percent of any number quickly, just move the decimal point one place to the left: 10 percent of 4,500 is 450.
Note: A percentage change can be negative. If a price falls from 100 to 80, the change is minus 20 percent, which the calculator shows as a decrease.
How do I calculate 20 percent of 150? Divide 20 by 100 to get 0.2, then multiply by 150. The answer is 30. You can also use the first box of this percentage calculator.
What is the percentage increase formula? Percentage increase = (New value minus Old value) divided by Old value, times 100. For example, a rise from 80 to 100 is (100 minus 80) divided by 80 times 100, which is 25 percent.
How do I find what percentage one number is of another? Divide the first number by the second number and multiply by 100. For example, 30 out of 200 is (30 divided by 200) times 100, which is 15 percent.
What is the difference between percent and percentage points? A percentage point is the simple difference between two percentages. If interest rises from 5 percent to 7 percent, it rose by 2 percentage points, which is a 40 percent increase in the rate itself.
How do I calculate a discount price? Multiply the price by the discount percent and divide by 100 to get the amount saved, then subtract it from the price. A 2,000 item with 25 percent off saves 500, so you pay 1,500.
Can percentages be more than 100 percent? Yes. A value can grow by more than 100 percent: if sales rise from 100 to 250, that is a 150 percent increase. But a part of a whole, like exam marks, cannot be more than 100 percent.
How do I calculate a percentage in my head? Start with 10 percent by moving the decimal point one place left, then build up: 20 percent is twice 10 percent, and 5 percent is half of 10 percent.
What is 100 percent of a number? It is the whole number itself. 100 percent of 250 is 250, and 200 percent of 250 is 500, which is double.