Calculators
Percentage Calculator
Three calculators in one: find a percentage of a number, work out what percent one number is of another, or measure the percentage change between two values.
15% of 200 is 30
How to calculate percentages
A percentage is a fraction out of 100. This tool covers the three calculations people reach for most often, each shown live as you type.
X% of Y = (X / 100) × YX is what % of Y = (X / Y) × 100Change = ((new - old) / old) × 100For example, 15% of 200 is 0.15 times 200, which is 30. The number 30 is (30 / 200) times 100, or 15%, of 200. And a move from 200 to 250 is a 25% increase, while 250 back to 200 is a 20% decrease, because each change is measured against its own starting value.
Common percentages
A quick reference for the percentages people use most, applied to round numbers.
| Percentage | of 100 | of 500 | of 1000 |
|---|---|---|---|
| 5% | 5 | 25 | 50 |
| 10% | 10 | 50 | 100 |
| 15% | 15 | 75 | 150 |
| 20% | 20 | 100 | 200 |
| 25% | 25 | 125 | 250 |
| 50% | 50 | 250 | 500 |
Frequently asked questions
How do I calculate a percentage of a number?
Convert the percentage to a decimal by dividing it by 100, then multiply by the number. For example, 20% of 80 is 0.20 times 80, which is 16.
How do I find what percentage one number is of another?
Divide the first number by the second, then multiply by 100. For example, 45 out of 180 is (45 / 180) times 100, which is 25%.
How do I calculate a percentage increase or decrease?
Subtract the old value from the new value, divide by the old value, then multiply by 100. A rise from 50 to 60 is ((60 - 50) / 50) times 100, a 20% increase.
What is the difference between percentage points and percent?
A move from 10% to 15% is a rise of 5 percentage points, but a 50% increase in relative terms. Percentage points compare the figures directly, while percent compares the change to the starting value.
How do I reverse a percentage to find the original value?
If a number already includes an added percentage, divide it by 1 plus the decimal rate. A price of 120 that includes 20% tax was 120 / 1.20, which is 100.