Work out percentages in seconds. Use the four calculators below to find a percentage of a number, see what percent one number is of another, measure a percentage change, or add and subtract a percentage. Results appear as you type.
All Free ToolsCalculatorsDiscount CalculatorLoan Calculator
What is X% of Y?
X is what percent of Y?
Percentage change from X to Y
Increase or decrease a number by a percentage
Results update as you type. Calculations happen in your browser.
What Is a Percentage?
A percentage is a way to write a part of 100. Saying 25% means 25 out of every 100, which is the same as one quarter. Percentages make it easy to compare amounts of different sizes, such as a discount on a coat and a discount on a car, or the growth of a small shop and a big one.
How to Calculate a Percentage
Percentage of a number
Multiply the number by the percentage and divide by 100. For example, 20% of 150 is 150 x 20 / 100 = 30.
What percent one number is of another
Divide the part by the total and multiply by 100. For example, 30 out of 150 is 30 / 150 x 100 = 20%.
Percentage change
Subtract the old value from the new value, divide by the old value and multiply by 100. For example, from 80 to 100 is (100 – 80) / 80 x 100 = 25% increase.
Increase or decrease by a percentage
Multiply the number by 1 plus the percentage as a decimal to increase it, or by 1 minus the percentage to decrease it. For example, 200 increased by 15% is 200 x 1.15 = 230.
Everyday Uses
- Finding the price after a sale, with the discount calculator.
- Working out a tip or a service charge on a bill.
- Checking how much a price, a salary or a bill has gone up or down.
- Calculating exam scores, such as 42 out of 60.
- Measuring growth in followers, visits or sales from one month to the next.
Common Mistakes to Avoid
- A percentage change is not the same in both directions. A drop from 100 to 50 is minus 50%, but going back from 50 to 100 is plus 100%.
- Taking 10% off and then adding 10% back does not return the original number, because the second 10% is worked out on a smaller amount.
- Percentage points and percent are different. Going from 10% to 12% is a rise of 2 percentage points, but a 20% increase in the rate.
Frequently Asked Questions
How do I calculate 20 percent of a number?
Multiply the number by 20 and divide by 100. You can also use the first calculator on this page and type 20 and your number.
How do I find what percent one number is of another?
Divide the first number by the second and multiply by 100. The second calculator does this for you.
How do I calculate percentage increase?
Subtract the old value from the new value, divide by the old value and multiply by 100. Use the third calculator for this.
Can the percentage be more than 100?
Yes. 150% of a number is one and a half times that number, and a value that doubles has increased by 100%.
Why does it say the value cannot be zero?
A percentage change or a percentage of a total cannot be worked out from zero, because dividing by zero has no answer.
Is this calculator free?
Yes. It is free to use, with no sign-up.
More Free Tools
Try the discount calculator, the loan calculator, the age calculator or the hours calculator, see all calculators, or browse all free online tools.