Find the part: 15% of 240
- Input
- Percentage = 15, Whole = 240
- Working
- Part = (15 / 100) × 240 = 0.15 × 240 = 36
- Result
- 15% of 240 = 36
Percentage Calculator
Work out percentages three ways — find the part, find the percent, or measure the change between two values — with full working shown for every answer. Runs entirely in your browser — your numbers never leave this device.
Calculation
Result
36
15% of 240 = 36
How it works
Part = (Percentage / 100) × Whole | Percentage = (Part / Whole) × 100 | Percent change = ((New − Old) / |Old|) × 100
| Fraction | Decimal | Percentage |
|---|---|---|
| 1/10 | 0.1 | 10% |
| 1/5 | 0.2 | 20% |
| 1/4 | 0.25 | 25% |
| 1/3 | 0.333… | 33.33% |
| 1/2 | 0.5 | 50% |
| 2/3 | 0.667… | 66.67% |
| 3/4 | 0.75 | 75% |
| 9/10 | 0.9 | 90% |
A percentage is a fraction out of 100, so every percentage question is one of three shapes: finding the part (15% of 240), finding the rate (45 is what percent of 180?), or finding the change between an old and a new value. Pick the shape, enter the two numbers you know, and the calculator substitutes them into the matching formula and shows the substitution line, not just the final answer.
Percent change always divides by the original value, never the new one — that is why going from 80 to 100 is a 25% increase while going back from 100 to 80 is only a 20% decrease. Results are shown to two decimal places and rounded half-up; the working line keeps the unrounded division so you can follow it with a hand calculator.
Edge cases are reported honestly rather than hidden: a whole of zero makes 'what percent is this of zero?' undefined, because division by zero has no answer, and the tool says so instead of printing 0%. Negative values are accepted and keep their sign, which matters for losses, temperature changes and negative growth.
Worked examples
Find the rate: 45 out of 180
- Input
- Part = 45, Whole = 180
- Working
- Percentage = (45 / 180) × 100 = 0.25 × 100 = 25
- Result
- 45 is 25% of 180
Percent increase: 80 to 100
- Input
- Old value = 80, New value = 100
- Working
- Change = 100 − 80 = 20. Percent change = (20 / 80) × 100 = 25
- Result
- 80 → 100 is a 25% increase
Frequently asked questions
How do I find what percent one number is of another?
Divide the part by the whole, then multiply by 100. For example, 45 / 180 = 0.25, and 0.25 × 100 = 25, so 45 is 25% of 180. The order matters: the number after the word 'of' is always the whole you divide by.
Why is 80 to 100 a 25% increase but 100 to 80 only a 20% decrease?
Percent change is always measured against the starting value. The change is 20 in both directions, but 20 / 80 = 25% on the way up and 20 / 100 = 20% on the way down. This is why a 50% loss needs a 100% gain to recover.
What is the difference between a percentage and a percentage point?
A percentage point is the plain arithmetic difference between two percentages. If a rate rises from 4% to 5%, that is a rise of 1 percentage point, but a 25% relative increase (1 / 4 × 100). News reports often mix the two up; this calculator works in relative percent change.
Can a percentage be more than 100%?
Yes. A percentage over 100% simply means the part is larger than the original whole — 260 is 130% of 200. Increases can also exceed 100%: tripling a value is a 200% increase, because the gain itself is twice the starting value.
What happens if I enter zero as the whole?
The calculation is undefined and the tool tells you so. Dividing by zero has no mathematical answer, so 'what percent is 5 of 0?' cannot be computed — any tool that prints 0% or 100% there is guessing.
Is my data uploaded anywhere when I use this calculator?
No. This calculator runs 100% in your browser — the numbers you type never leave your device, nothing is uploaded to a server, and there is no account, history or tracking of the values you enter. Closing the tab clears everything.
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