➗ Percentage Calculator
Percentages are everywhere: discounts, interest, VAT and grades. This calculator answers the three most common percentage questions in a single click: how much is X% of Y, what percentage X is of Y, and how much something increased or decreased in percent.
Formula
X% of Y = (X ÷ 100) × Y · X as % of Y = (X ÷ Y) × 100 · Change = ((B − A) ÷ A) × 100
A percentage is a part per hundred. 25% means 25 out of every 100. To find 25% of 200 you divide 25 by 100 (= 0.25) and multiply by 200, giving 50. To find what percentage X is of Y, divide X by Y and multiply by 100. For a percentage change, work out the difference between the new and old value, divide by the old value, and multiply by 100.
Steps
- 1Choose what to calculate: X% of Y, X as % of Y, or the change from A to B.
- 2Enter the two values.
- 3Read the answer instantly, including the working.
Common percentages of 100
| Percentage | Of 100 | Of 50 |
|---|---|---|
| 5% | 5 | 2.5 |
| 10% | 10 | 5 |
| 25% | 25 | 12.5 |
| 50% | 50 | 25 |
| 75% | 75 | 37.5 |
| 100% | 100 | 50 |
Quick lookup without calculating; use the calculator above for other values.
commonMistakes
- Forgetting that a 50% increase followed by a 50% decrease does not return to the starting value.
- Confusing percent and percentage points when comparing two percentages.
- Using the wrong base value for a percentage change (always the old/original value).
useCases
- Working out discounts in-store or online.
- Converting grades, exam scores or statistics into percentages.
- Comparing salary raises, interest rates or price changes.