How to Calculate a Percentage: Formula and Examples

Learn how to calculate a percentage step by step with the formula, real examples and a free calculator.

Calculating percentages is a very useful skill in everyday life: discounts, tips, VAT, pay rises or exam grades. In this guide we explain the formula and several examples, and at the end you have a calculator to do it instantly.

1 The basic formula

To calculate "X percent of Y" use: (X × Y) ÷ 100. That is, multiply the percentage by the amount and divide by 100.

2 Example 1: 20% of 150

Apply (20 × 150) ÷ 100 = 3000 ÷ 100 = 30. So 20% of 150 is 30.

3 Example 2: find what percentage it is

To find out what percentage A is of B, use (A ÷ B) × 100. If 50 is what % of 200: (50 ÷ 200) × 100 = 25%.

4 Calculate increases and discounts

For a discount, calculate the percentage and subtract it from the total. For an increase, calculate it and add it. The percentage and discount calculators do this automatically.

Try it with our free tool

Percentage Calculator

Use the tool

Frequently Asked Questions

How do I calculate a percentage of an amount?
Multiply the amount by the percentage and divide by 100. For example, 15% of 200 is (15 × 200) ÷ 100 = 30.
How do I know what percentage one number is of another?
Divide the number by the total and multiply by 100. Example: 40 out of 160 is (40 ÷ 160) × 100 = 25%.
What steps do I take to calculate a discount?
First calculate the discount percentage on the original price and then subtract it from the price. For example, 25% of €80 is €20 off; the final price is €60.

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