Percentage calculator
Choose what you want to find, enter two numbers and see the answer with the steps.
Three common percentage questions
What is X% of Y? Multiply: X / 100 x Y. For 15% of 80: 15 / 100 x 80 = 12.
X is what percent of Y? Divide and multiply by 100: X / Y x 100. For 12 out of 80: 12 / 80 x 100 = 15%.
What is the percent change from X to Y? (Y - X) / X x 100. From 80 to 100: (100 - 80) / 80 x 100 = 25%. From 100 down to 80 it is -20%.
| Number | 10% | 15% | 20% | 25% |
|---|---|---|---|---|
| 20 | 2 | 3 | 4 | 5 |
| 40 | 4 | 6 | 8 | 10 |
| 50 | 5 | 7.5 | 10 | 12.5 |
| 80 | 8 | 12 | 16 | 20 |
| 120 | 12 | 18 | 24 | 30 |
| 250 | 25 | 37.5 | 50 | 62.5 |
Why a rise and a fall are not symmetric
A 25% increase from 80 gives 100, but going back from 100 to 80 is a 20% decrease, because the base changed. Percent change always uses the starting number as the base.
For schoolwork
To turn a test score into a percent and letter, use the test score calculator.
Questions people ask
How do I calculate a percentage of a number?
Divide the percent by 100 and multiply by the number. 15% of 80 is 0.15 x 80 = 12.
How do I find what percent one number is of another?
Divide the first by the second and multiply by 100.
How do I calculate percent increase?
Subtract the old value from the new one, divide by the old value and multiply by 100.
Can the percent be above 100?
Yes. 150 is 150% of 100, and a number that triples has increased by 200%.