Percentage Calculator
Answer a percentage question three ways: what is X% of Y, X is what percent of Y, or X is Y% of what number. Pick the phrasing that matches your question — each one solves the same equation for the piece you’re missing, and shows the working.
How to calculate a percentage of a number
A percentage is just a fraction of 100, so “20%” means 20 / 100 = 0.2. To take a percent of a number, multiply:
part = (percent / 100) × whole
Rearranged, the same relationship answers the other two questions: percent = part / whole × 100 and whole = part / (percent / 100).
Worked examples
- What is 20% of 150? → 0.2 × 150 = 30.
- 30 is what percent of 150? → 30 / 150 × 100 = 20%.
- 30 is 20% of what number? → 30 / 0.2 = 150.
Percentage table
Common percentages of a few round amounts:
| Percent | of 20 | of 50 | of 100 | of 250 | of 1,000 |
|---|---|---|---|---|---|
| 1% | 0.2 | 0.5 | 1 | 2.5 | 10 |
| 5% | 1 | 2.5 | 5 | 12.5 | 50 |
| 10% | 2 | 5 | 10 | 25 | 100 |
| 15% | 3 | 7.5 | 15 | 37.5 | 150 |
| 20% | 4 | 10 | 20 | 50 | 200 |
| 25% | 5 | 12.5 | 25 | 62.5 | 250 |
| 50% | 10 | 25 | 50 | 125 | 500 |
| 75% | 15 | 37.5 | 75 | 187.5 | 750 |
Frequently asked questions
How do I find a percentage of a number quickly?
Divide the percent by 100, then multiply by the number. For 20% of 150: 20 / 100 = 0.2, and 0.2 x 150 = 30. For a rough estimate, 10% is the number with the decimal point moved one place left.
How do I turn a fraction into a percentage?
Divide the top number by the bottom number and multiply by 100. For example, 30 out of 150 is 30 / 150 = 0.2, which is 20%.
Can a percentage be more than 100%?
Yes. A percentage over 100% just means the part is larger than the whole it is compared to. 300 is 200% of 150.