Percentage Calculator

Find X% of a number, what percent one number is of another, or the percentage change between two values. Results update as you type and show the working.

Percentage (X)

Of number (Y)

Result

15% of 240 is 36.15 ÷ 100 × 240 = 36

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How to use it

Pick the question you want answered: “What is X% of Y?”, “X is what % of Y?” or “% change from X to Y”.
Type your two numbers. Decimals and negative numbers are fine.
Read the answer and the one-line calculation underneath. Use Copy to paste the result elsewhere.

Examples

15% of 240

Choose “What is X% of Y?”, enter 15 and 240. The answer is 36, because 15 ÷ 100 × 240 = 36.

Test score as a percentage

You scored 42 out of 50. Choose “X is what % of Y?”, enter 42 and 50: 42 ÷ 50 × 100 = 84%.

Price change

Rent went from $1,400 to $1,512. Choose “% change”, enter 1400 and 1512 to get an 8% increase.

The three percentage formulas

A percentage is a fraction of 100, so every percentage question is a multiplication or division with 100 in it. Finding X% of Y multiplies Y by X/100. Finding what percent X is of Y divides X by Y and multiplies by 100.

Percentage change compares the difference between two values with the starting value. Because it is measured against where you started, a rise from 50 to 100 is +100% while a fall from 100 to 50 is only −50%.

X% of Y = X ÷ 100 × Y · X as % of Y = X ÷ Y × 100 · change = (new − old) ÷ |old| × 100

Frequently asked questions

How do I calculate a percentage of a number in my head?

Find 10% by moving the decimal point one place left, then scale. For 15% of 240: 10% is 24, 5% is half of that (12), so 15% is 36.

Why isn't a 50% drop undone by a 50% rise?

Each percentage is measured from a different starting value. 100 falls 50% to 50, but a 50% rise on 50 only adds 25, giving 75. You would need a 100% rise to get back to 100.

What's the difference between percent and percentage points?

Percentage points are the plain difference between two percentages. An interest rate moving from 4% to 5% rose one percentage point, which is a 25% increase in the rate itself.

Can the result be more than 100%?

Yes. If X is larger than Y, X is more than 100% of Y — for example, 30 is 150% of 20. Percentage increases can also exceed 100%.

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More in Calculators · Last reviewed September 2026