Percentage Calculator
Three common percentage questions, answered instantly — no formula to remember.
What is X% of Y?
X is what % of Y?
Percent change, X to Y
Three percentage questions, one tool
Percentages come up constantly — discounts, tips, grades, growth rates — but the three common questions (finding a percentage of a number, finding what percentage one number is of another, and finding percent change) each use a different formula. This tool covers all three at once, live as you type, so there's no formula to look up or remember.
Also useful: Tip Calculator and Unit Converter.
Frequently asked questions
Multiply Y by X divided by 100 — for example, 20% of 150 is 150 × (20 / 100) = 30.
Percent change is (new value − old value) ÷ old value × 100. A positive result is an increase; a negative result is a decrease.
A negative percent change means the new value is smaller than the old one — it's a decrease, not an error.