Percentage calculator
ReadyFind X% of a number, what percentage one number is of another, the percentage change between two values, and a value increased or decreased by a percentage.
How to use
- Choose the type of calculation: A × B%, A as a % of B, change from A to B, A plus B%, or A minus B%.
- Enter A and B – the result and the formula appear straight away.
- Percentage change also shows the difference and the ratio between the two values.
Formula
- B% of A = A × B ÷ 100
- A as a % of B = A ÷ B × 100
- Change (%) = (B − A) ÷ |A| × 100
- A increased by B% = A × (1 + B ÷ 100); decreased = A × (1 − B ÷ 100)
Worked example
15% of 200 → 30 30 is 15% of 200 30,000 → 36,000 is a +20% change (difference 6,000, ×1.2) 50,000 decreased by 20% → 40,000
FAQ
What’s the difference between percent and percentage points?
If an interest rate goes from 3% to 4%, it rose by 1 percentage point, but by (4 − 3) ÷ 3 × 100 ≈ 33.3% in relative terms.
If something rises 10% and then falls 10%, is it back where it started?
No. 100 up 10% is 110, and 110 down 10% is 99, because the second percentage is taken from a bigger base.
What if the starting value is 0?
Percentage change from 0 isn’t defined because you can’t divide by zero. Compare the difference (B − A) instead.