Everyday Calculators & Converters
Percentage Calculator
Four common percentage questions, answered as you type, with the working shown step by step.
- Runs in your browser
- Working shown
What do you want to work out?
The answer
Enter both numbers.
The answer and the working appear here as you type.
Working
How it works
Four formulas, worked out at full precision and rounded only for display.
- X % of Y
- Y × X ÷ 100. 20% of 150 is 150 × 0.2 = 30.
- % change
- (new − old) ÷ the size of the old value × 100. 80 → 100 is a 25% increase. With a negative old value the wording still follows whether the number went up or down. The old value can’t be 0.
- A is what % of B
- A ÷ B × 100. 30 is 20% of 150. B can’t be 0.
- Increase / decrease by %
- Base × (1 + percent ÷ 100). Use a negative percent to decrease: 200 decreased by 15% is 200 × 0.85 = 170.
- Rounding
- Up to 6 decimal places, with digit grouping. Results under 0.001 are shown in scientific form, like 1.235 × 10⁻⁴.
Questions
What are the four formulas?
X% of Y is Y × X ÷ 100. Percentage change from A to B is (B − A) ÷ A × 100. A as a percent of B is A ÷ B × 100. A increased or decreased by B% is A × (1 + B ÷ 100); use a negative percent to decrease.
What’s the difference between percent and percentage points?
Percentage points are the plain difference between two percentages: 5% to 7% is up 2 percentage points. Percent change compares it to the starting value: 5% to 7% is a 40% increase. This calculator works out percent change.
How does it handle negative numbers?
Percentage change divides by the size of the old value, so the wording follows whether the number went up or down: −50 to −25 is a 50% increase. An old value of 0 has no percentage change, and the calculator says so.
How are results rounded?
Results are shown with up to 6 decimal places and digit grouping. Very small results, under 0.001, are shown in scientific form, like 1.235 × 10⁻⁴.