Percentage Calculator
The three percentage questions everyone actually asks. Answered live.
1. What is X% of Y?
2. X is what percent of Y?
3. Percentage change from X to Y
How it works
Each calculator applies its formula the moment you type, using plain arithmetic you can verify yourself: no rounding tricks, no server round-trips. Percentages express a part relative to a whole, so the “of” value is always your reference point. Change is measured against the old value: a rise from 50 to 65 is a 30% increase, while a fall from 65 to 50 is a 23.08% decrease.
FAQ
How do I calculate a percentage of a number?
Multiply the number by the percentage divided by 100. For example, 15% of 80 = 80 × 0.15 = 12.
How is percentage change calculated?
(New − Old) ÷ |Old| × 100. A negative result means a decrease. Dividing by the absolute value keeps the formula correct even when the old value is negative.
What’s the difference between percent and percentage points?
Moving from 10% to 12% is an increase of 2 percentage points, but a 20% relative increase (2 ÷ 10 × 100). News headlines usually mean percentage points; calculators can mean either, so this one gives both views via calculator 3 and calculator 2.