Percentage Calculator
Three common percentage questions, one page. Pick a tab and type — results update live.
Your details
How this is calculated
X% of Y multiplies Y by X ÷ 100. Example: 25% of 200 = 50.
X is what % of Y divides X by Y and multiplies by 100. Example: 25 is 12.5% of 200.
% change from A to B is (B − A) ÷ |A| × 100. A positive result is an increase; a negative result is a decrease.
Who this calculator is for
This is aimed at anyone who needs a quick, reliable answer without opening a spreadsheet — at the till, in a meeting, or while checking someone else's arithmetic. It is built to be fast on a phone, because that is usually where these questions come up.
Assumptions and accuracy
The arithmetic is exact, but results are rounded for display, so a figure may differ by a penny from a till receipt that rounds at a different step. Where currency is involved, the calculator does not apply any regional rounding rules.
Frequently asked questions
Related calculators
See every calculator on the homepage, browse our free online tools, or read the guides on our blog.