How this calculator works
This calculator finds a percentage of any number. It answers questions like “what is 20% of 150?”, which come up when you work out a commission, a share of a budget, a test section's weight or how much of a bill is tax.
A percentage is simply a number out of 100, so 20% means 20 out of every 100. To find it, turn the percentage into a decimal by dividing by 100, then multiply by the number.
Worked example: 15% of $240
- Turn the percentage into a decimal: 15 ÷ 100 = 0.15.
- Multiply by the number: 0.15 × 240 = 36.
15% of $240 is $36.
Quick reference: common percentages of 200
| Percentage | As a decimal | Of 200 |
|---|---|---|
| 5% | 0.05 | 10 |
| 10% | 0.10 | 20 |
| 15% | 0.15 | 30 |
| 20% | 0.20 | 40 |
| 25% | 0.25 | 50 |
| 50% | 0.50 | 100 |
| 75% | 0.75 | 150 |
Common mistake
Multiplying by the whole percentage instead of the decimal. 15 × 240 = 3,600, which is 100 times too big. Always divide the percentage by 100 first.
Questions people ask
- Is there a quick way to find 10%?
- Yes. Move the decimal point one place to the left: 10% of 240 is 24. From there, 5% is half of that (12) and 20% is double (48).
- Does X% of Y equal Y% of X?
- Yes. 8% of 50 and 50% of 8 are both 4, so you can swap the numbers if one way is easier to work out in your head.
- Can I find a percentage over 100%?
- Yes. 150% of 80 is 1.5 × 80 = 120. Anything over 100% gives a result larger than the starting number.
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