Percentage Calculator
The three percentage questions everyone actually asks — answered instantly, with the formula shown for each.
| Formula used | — |
| Reverse check | — |
The three percentage formulas
| Question | Formula | Example |
|---|---|---|
| What is 15% of 240? | 240 × 15 ÷ 100 | 36 |
| 36 is what % of 240? | 36 ÷ 240 × 100 | 15% |
| Change from 240 to 276? | (276 − 240) ÷ 240 × 100 | +15% |
The percentage-change asymmetry
A 50% loss needs a 100% gain to recover — percentage changes are not symmetric because the base changes. A stock falling from $100 to $50 dropped 50%; climbing back from $50 to $100 is a 100% rise. The same trap appears in salaries: a 10% cut followed by a 10% raise leaves you at 99% of where you started.
Percentage points vs percent
An interest rate moving from 4% to 5% rose one percentage point, but 25 percent. News headlines mix these constantly; the difference moves markets and mortgage payments.
Frequently asked questions
How do I calculate a percentage of a number?
Multiply the number by the percent and divide by 100. 15% of 240 = 240 × 15 ÷ 100 = 36. Mental shortcut: 10% is one decimal shift (24), and 15% is that plus half again (24 + 12 = 36).
How do I work out what percent one number is of another?
Divide the part by the whole, times 100. 36 of 240 → 36 ÷ 240 × 100 = 15%.
How is percentage change calculated?
New minus old, divided by the old value, times 100. From 240 to 276: (276 − 240) ÷ 240 × 100 = +15%. Falling from 276 to 240 is −13.04%, not −15% — the base changed.
What is the difference between percent and percentage points?
Points measure the absolute gap between two percentages; percent measures relative change. A rate going 4% → 5% is +1 point but a 25% relative increase.
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Last updated: 2026-07-08