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Percentage Calculator

Three common percentage questions in one place: what is 15% of 80, 12 is what percent of 80, and what is the percent change from 50 to 65.

Result

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How to use this calculator

  1. Choose the question you want to answer from the first menu.
  2. Enter the two numbers. The labels change to show which number goes where.
  3. The answer updates as you type. Press Calculate or Enter to move focus to the result.

The formula

X% of Y = (X ÷ 100) × Y X is what % of Y = (X ÷ Y) × 100 Percent change = (New − Old) ÷ |Old| × 100

A percent is a ratio out of 100. Percent change compares the difference to the starting value, which is why a rise from 50 to 65 (+30%) and a fall from 65 to 50 (−23.08%) are not the same size. The U.S. Bureau of Labor Statistics uses the same percent-change formula for price indexes.

Worked example

Three quick examples

  1. 15% of 80: 15 ÷ 100 = 0.15, and 0.15 × 80 = 12.
  2. 12 is what percent of 80: 12 ÷ 80 = 0.15, and 0.15 × 100 = 15%.
  3. Change from 50 to 65: 65 − 50 = 15, 15 ÷ 50 = 0.30, so +30%. From 80 down to 60: −20 ÷ 80 = −25%.

Enter any of these pairs above to check them.

Percent vs. percentage points

If an interest rate goes from 4% to 5%, it rose by 1 percentage point, but by 25 percent (1 ÷ 4 × 100). News reports and loan offers often mix these up, so check which one is meant.

Frequently asked questions

How do I calculate a percentage of a number?

Divide the percentage by 100 and multiply by the number. For 20% of 250: 0.20 × 250 = 50.

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

Divide the part by the whole and multiply by 100. 45 out of 60 is 45 ÷ 60 × 100 = 75%.

What is the difference between percent change and percent difference?

Percent change measures movement from an old value to a new one and divides by the old value. Percent difference compares two values with no direction and usually divides by their average. This calculator does percent change.

Can a percent change be more than 100%?

Yes. Going from 20 to 50 is a 150% increase. A decrease can never be more than 100% for positive values, because falling to zero is −100%.

Why does a 50% drop followed by a 50% rise not get me back to where I started?

Because the second percentage applies to a smaller base. 100 falls 50% to 50, then rises 50% to 75.

Sources

Last reviewed November 6, 2026. Calculations run in your browser; nothing you type is sent to us. Spotted a mistake? Tell us.