How do I calculate a percentage of a number?

Multiply the number by the percentage divided by 100. For example, 15% of 200 = (15/100) × 200 = 30.

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

Divide the first number by the second, then multiply by 100. For example, 30 is what percent of 200? (30/200) × 100 = 15%.

How do I calculate reverse percentage?

If X% of a number equals Y, divide Y by (X/100). For example, 15% of what is 30? 30 / (15/100) = 200.

What is the difference between percentage and percentage points?

A percentage is a proportion of a whole. A percentage point is the arithmetic difference between two percentages. If a rate goes from 5% to 10%, that is a 5 percentage point increase but a 100% increase.

Percentage Calculator

Quick percentage calculations. Choose a mode, enter your numbers, get the answer instantly.

Percentage (%)

Number

15% of 200

(15 ÷ 100) × 200 = 30

How Percentages Work

Three common percentage problems and how to solve them.

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Percentage of a Number

Find X% of Y. Multiply Y by X divided by 100. Example: 15% of 200 = (15/100) × 200 = 30. Used for tips, taxes, discounts, and commissions.

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What Percent

Find what percent X is of Y. Divide X by Y, multiply by 100. Example: 30 out of 200 = (30/200) × 100 = 15%. Used for scores, shares, and progress.

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Reverse Percentage

Find the whole when you know a percentage and its value. Divide the value by (percent/100). Example: 15% of what = 30? 30 / (15/100) = 200.

Frequently Asked Questions

Common questions about percentage calculations.

Multiply the number by the percentage divided by 100. The formula is: (percentage / 100) × number. For example, 15% of 200 = (15/100) × 200 = 30. This works for any percentage and any number.

Divide the part by the whole, then multiply by 100. Formula: (part / whole) × 100. For example, if you scored 30 out of 40 on a test: (30/40) × 100 = 75%. The result tells you the percentage the part represents of the whole.

When you know the percentage and its resulting value but need the original number, divide the result by (percentage/100). Formula: result / (percentage / 100). Example: if 15% of a number is 30, then 30 / (15/100) = 200. This is common in tax and discount calculations.

Subtract the original value from the new value, divide by the original value, then multiply by 100. Formula: ((new - original) / original) × 100. A positive result is an increase; a negative result is a decrease.

A percentage is a proportion of a whole. A percentage point is the arithmetic difference between two percentages. If a tax rate goes from 5% to 10%, that is a 5 percentage point increase but a 100% increase. Percentage points describe the gap; percentages describe the relative change.