Percentage Calculator

Solve common percentage tasks: what a percent of a value is, what percent one value is of another, and what whole a part represents.

What does this Percentage Calculator do?

This Calculator solves three everyday percentage tasks: finding what X% of Y is, finding what percent X is of Y, and finding the whole when X is Y% of an unknown amount. Each mode uses a different formula but the same two-value input pattern.

Formula

What is X% of Y? Result = Y × (X ÷ 100). X is what % of Y? Result = (X ÷ Y) × 100. X is Y% of what? Result = X ÷ (Y ÷ 100). In the second mode, Y cannot be zero. In the third mode, Y cannot be zero.

Worked example

To find 25% of 200, multiply 200 by 0.25 to get 50. To find what percent 50 is of 200, divide 50 by 200 and multiply by 100 to get 25%. To find the whole when 50 is 25% of an unknown value, divide 50 by 0.25 to get 200.

Assumptions and limitations

The Calculator treats all inputs as plain numbers without units, currency symbols, or formatting. It does not interpret business-specific definitions such as margin versus markup, which use different denominators.

Common questions

How is this different from percentage change?

Percentage change compares a starting value to an ending value over time. This Calculator solves static part-whole percentage tasks. Why is zero rejected in some modes? Dividing by zero would make the percentage or whole undefined in those formulas. Can I enter decimals? Yes. Decimal inputs are supported for all fields.

Methodology

The Calculator validates inputs with exact decimal arithmetic, selects the formula for the chosen mode, and rounds only the displayed result.