Percentage Calculator

Three everyday percentage questions in one place. Choose what you want to find, enter two numbers and press Calculate.

Result

Enter values and press Calculate to see the result.

Formula

X% of Y=X100×YX\% \text{ of } Y = \frac{X}{100} \times Y

A percentage is a number of hundredths, so X% means X ÷ 100.

percent=partwhole×100%\text{percent} = \frac{\text{part}}{\text{whole}} \times 100\%

Divide the part by the whole, then multiply by 100.

change=new−original∣original∣×100%\text{change} = \frac{\text{new} - \text{original}}{|\text{original}|} \times 100\%

A positive result is an increase and a negative result is a decrease, measured relative to the original value.

How to use this calculator

  1. Choose the question you want to answer.
  2. Enter the two numbers. Decimals such as 12.5 and negative values are allowed.
  3. Press Calculate. Changing an input afterwards marks the result as outdated until you calculate again.
  4. If a result had to be rounded, it is labelled approximate and the exact fraction is shown too.

Worked example

What is 15% of 80?

15% means 15 hundredths: 15 ÷ 100 = 0.15.

Multiply by 80: 0.15 × 80 = 12.

So 15% of 80 is 12.

Frequently asked questions

Is percentage change the same as percentage points?

No. Going from 10% to 15% is a change of 5 percentage points, but a 50% increase relative to the original 10%. This calculator gives the relative change.

Why can’t I calculate a change from 0?

Percentage change divides by the original value. When the original value is 0 the division is undefined, so no percentage can be given — Sumzo tells you this instead of showing a misleading number.

Does an increase of 20% followed by a decrease of 20% bring me back to the start?

No. 100 increased by 20% is 120, and 120 decreased by 20% is 96. Each percentage is measured from a different starting value.

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