Calculator
Calculation
Result25%
Method and variables
Percentage Calculator
Formula: percentage = (part / whole) x 100
Assumption: The whole must not be zero, and both values must use the same basis.
Worked example
Percentage Calculator
15 out of 60 is (15 / 60) x 100 = 25%.
Three percentage questions
| Question | Formula | Example | Answer |
|---|---|---|---|
| What % is A of B? | A / B × 100 | 18 of 72 | 25% |
| What is P% of B? | B × P / 100 | 15% of 240 | 36 |
| Percentage change from A to B | (B − A) / A × 100 | 80 → 92 | 15% |
| Original value before a P% rise | B / (1 + P/100) | 120 after a 20% rise | 100 |
Percentage points and percent are different: an interest rate rising from 4% to 5% has gone up by one percentage point, which is a 25% increase relative to the starting rate. Likewise, a 20% discount followed by a 20% price rise does not return to the original price: 100 × 0.8 × 1.2 = 96.
Common mistakes
- Dividing by the wrong base: percentage change always divides by the starting value.
- Removing a percentage by subtracting it: to remove 20% VAT from 120, divide by 1.2 (= 100), do not subtract 20% of 120 (= 96).