How do I calculate a percentage of a number?

Multiply the number by the percentage, then divide by 100. For 15% of 80: 80 × 15 ÷ 100 = 12.

How do I find what percent one number is of another?

Divide the part by the whole and multiply by 100. 12 of 80 is 15%.

Why doesn't a 50% loss get undone by a 50% gain?

The gain applies to a smaller amount. Lose 50% of 100 and you have 50. Gain 50% of 50 and you have 75, not 100.

Percentage Calculator

Three everyday questions in one place: what is X% of Y, X is what percent of Y, and how much has a value changed in percent.

Quick Percentages

What is X% of Y?

% of

X is what percent of Y?

is what % of

Percentage change from X to Y

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20% of 150 is 30. Divide the percentage by 100, then multiply.

Three everyday percentage calculations: a percentage of a number, what percent one number is of another, and the percentage change between two values.

Formula

% of X: value × percentage ÷ 100. What percent: part ÷ whole × 100. Change: (new − old) ÷ |old| × 100.

Reference Values

•15% of 80 = 12
•12 of 80 = 15%
•Percentage change uses the old value as the base

FAQ

Common questions about Percentage Calculator

How we calculate this

We use the standard published formula for this calculation, and we show the working so you can check it.

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