Percentage Calculator
Calculate any percentage instantly. Find X% of Y, what percentage one number is of another, the whole value, or the percentage change between two numbers.
Last updated September 6, 2026
What is A% of B?
30
20 ÷ 100 × 150 = 30
How to Use the Percentage Calculator
Choose the calculation you want to perform, enter your numbers, and the result is calculated instantly. You can use the calculator to solve the four most common types of percentage problems.
| Calculation | Example |
|---|---|
| A percentage of a number | What is 20% of 150? |
| What percentage one number is of another | 30 is what percentage of 150? |
| The whole number from a percentage | 30 is 20% of what number? |
| Percentage change | What is the percentage change from 80 to 100? |
You can enter whole numbers or decimals, and no signup is required. Calculations run directly in your browser.
Percentage Formulas
A percentage represents a number as a fraction of 100. The formula you use depends on which part of the percentage problem you are trying to find.
| Question | Formula |
|---|---|
| What is A% of B? | (A ÷ 100) × B |
| A is what percentage of B? | (A ÷ B) × 100 |
| A is B% of what number? | A ÷ (B ÷ 100) |
| Percentage change from A to B | ((B − A) ÷ |A|) × 100 |
Percentage Calculation Examples
What is 20% of 150?
20 ÷ 100 × 150 = 30
Answer: 30
30 is what percentage of 150?
30 ÷ 150 × 100 = 20%
Answer: 20%
30 is 20% of what number?
30 ÷ 0.20 = 150
Answer: 150
What is the percentage change from 80 to 100?
(100 − 80) ÷ 80 × 100 = 25%
Answer: 25% increase
What Is a Percentage?
A percentage expresses a number as a fraction of 100. The word percent means “per hundred,” so 25% means 25 out of every 100, or 0.25 as a decimal.
Percentages are commonly used for discounts, tips, taxes, grades, financial changes, statistics, interest rates, and comparing values.
For example, 20% of 200 is 40 because: 0.20 × 200 = 40
Frequently asked questions
How do I calculate a percentage of a number?
Divide the percentage by 100 and multiply the result by the number. Example: 25% of 200 = 50.
How do I find what percentage one number is of another?
Divide the first number by the second and multiply by 100. Example: 30 ÷ 150 × 100 = 20%.
How do I find the original number from a percentage?
Divide the known value by the percentage expressed as a decimal. Example: 30 ÷ 0.20 = 150.
Can a percentage be greater than 100%?
Yes. 150 is 150% of 100.
Why can percentage change be negative?
A negative percentage change means the value decreased.
What is the difference between percentage change and percentage points?
Percentage change measures relative change; percentage points measure the arithmetic difference between two percentages.
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