Percentage Calculator
Work out X% of a number, what percentage one number is of another, the percentage change, or the price after a discount.
Tip: To add a percentage to a value, multiply by 1 plus the rate. For example, adding 20% means multiplying by 1.20.
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About this digital tool
A percentage calculator helps you answer four everyday questions: what X% of a number is, what share one number is of another, how much a value has changed in percentage terms, and what price remains after a discount. Choose the right tab, enter two numbers and read the result immediately, with no formula to remember. A percentage is a part of 100, so X% of Y equals Y × X ÷ 100. For example, 20% of 150 is 150 × 20 ÷ 100 = 30. If a product costs 80 and is reduced by 25%, the new price is 60. Going back up from 60 to 80 is an increase of about 33%, not 25%, because the starting value changes. Percentages are useful for students, shopping with offers, pay rises and business reports.
How to use
- Choose the calculation you need.
- Enter the matching values.
- Read the result straight away.
Frequently asked questions
How do I calculate percentage change?
Use (new value − old value) ÷ old value × 100. A positive result means an increase and a negative result means a decrease.
How do I find what percentage 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 work out 15% of a number?
Multiply the number by 15 and divide by 100. For example, 15% of 200 is 200 × 15 ÷ 100 = 30.
How do I calculate the price after a discount?
Final price = original price × (1 − discount ÷ 100). For example, 120 with a 25% discount is 120 × 0.75 = 90, so you save 30.