Percentage Calculator
A percentage expresses a number as a fraction of 100. This calculator answers the three questions people ask most often: what a given percentage of a number is, what percentage one number is of another, and the percentage change between two values.
Percentage Calculator
Free online percentage calculation tool
Formulas
- X% of Y
Result = (X ÷ 100) × Y - X is what % of Y
Percentage = (X ÷ Y) × 100 - Percentage change from A to B
Change = ((B − A) ÷ |A|) × 100
Watch out: Percentage change is not symmetric. A rise from 100 to 150 is +50%, but the fall from 150 back to 100 is only −33.3%.
Percentage quick reference
Each cell shows the given percentage of the number at the top of its column.
| Percentage | of 50 | of 100 | of 200 | of 500 | of 1,000 |
|---|---|---|---|---|---|
| 5% | 2.5 | 5 | 10 | 25 | 50 |
| 10% | 5 | 10 | 20 | 50 | 100 |
| 15% | 7.5 | 15 | 30 | 75 | 150 |
| 20% | 10 | 20 | 40 | 100 | 200 |
| 25% | 12.5 | 25 | 50 | 125 | 250 |
| 30% | 15 | 30 | 60 | 150 | 300 |
| 50% | 25 | 50 | 100 | 250 | 500 |
| 75% | 37.5 | 75 | 150 | 375 | 750 |
When you would use it
Discounts and tips, exam grades, statistics, interest rates, and tracking growth or decline.
Frequently asked questions
How do I work out a percentage of a number?
Divide the percentage by 100 and multiply by the number. For example, 15% of 80 is 0.15 × 80 = 12.
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 calculate percentage increase or decrease?
Subtract the old value from the new one, divide by the old value, and multiply by 100. Going from 80 to 100 is (100 − 80) ÷ 80 × 100 = a 25% increase.
Why is a 50% rise followed by a 50% fall not back where it started?
Each percentage applies to a different base. 100 rises by 50% to 150, but 50% of 150 is 75, so falling by 50% leaves 75 — a net loss of 25%.