Percentage Calculator
X% of Y, what percent one number is of another, percentage change, or adding/subtracting a percentage — pick a mode and get an instant answer.
Four ways people actually need to calculate a percentage
Most "percentage calculator" searches boil down to one of four questions: what's X% of a number, what percentage one number is of another, how much something changed in percentage terms, or what a number becomes after adding or subtracting a percentage. This tool covers all four in one place instead of making you do the arithmetic by hand.
The formulas
- X% of Y: (X ÷ 100) × Y
- X is what % of Y: (X ÷ Y) × 100
- Percentage change: ((To − From) ÷ |From|) × 100
- Add/subtract a percentage: Base ± (Base × Percent ÷ 100)
Frequently asked questions
So the direction (increase/decrease) is reported correctly even when the starting value is negative — a standard convention in percentage-change calculations.
'X% of Y' answers a question like "what is 15% of 200?" (answer: 30). 'X is what % of Y' answers the reverse: "30 is what percent of 200?" (answer: 15%).