Percentage Calculator covers the three most common percentage questions in a tabbed layout: what is X% of Y, what percentage is X of Y, and what is the percentage change from X to Y. All results update live as you type.
Percentage change is ((new value - old value) / old value) × 100. A positive result means an increase; a negative result means a decrease.
If the denominator would be zero, the result shows '—' instead of infinity or an error, keeping the interface clean and avoiding confusing output.
'X% of Y' answers 'what is 20% of 50?' (= 10). 'X is what % of Y' answers 'what percent is 10 of 50?' (= 20%). They're inverse operations.
Use 'X% of Y' to find the discount amount (e.g. 20% of $50 = $10), then subtract from the original price, or use percentage change mode to go directly from original to discounted price.
Yes — if a value more than doubles, the percentage increase exceeds 100%. For example, going from 10 to 25 is a 150% increase.
Yes — percentage change works with negative values, though interpretation depends on context (e.g. a 'decrease' from a negative number can be mathematically counterintuitive).
Yes — all three modes calculate results instantly as you type, with no calculate button needed.
