Percentage Calculator

Work out any percentage and see every step, animated, with your own numbers.

Answer

15% of 200 is 30.

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All steps as text

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How to use this calculator

Choose what you want to work out with the buttons at the top of the calculator.
Type your numbers. The answer updates as you type, and you can use commas, decimals or fractions like 2 1/2.
Under Show me how, press Play to watch each step, or use Back and Next to go at your own pace.

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The percentage formulas

Percent of a number

\text{Part} = \frac{P}{100} \times \text{Number}

What percent one number is of another

P = \frac{\text{Part}}{\text{Whole}} \times 100

Find the whole from a part and a percentage

\text{Whole} = \text{Part} \div \frac{P}{100}

Percentage change

\%\ \text{change} = \frac{\text{New} - \text{Old}}{\lvert \text{Old} \rvert} \times 100

Increase or decrease by a percentage

\text{Result} = \text{Number} \times \left(1 \pm \frac{P}{100}\right)

Worked examples

What is 15% of 200?

15% means 15 out of every 100, so turn it into a decimal: 15 ÷ 100 = 0.15. Then multiply: 0.15 × 200 = 30. So 15% of 200 is 30.

45 is what percent of 60?

Divide the part by the whole: 45 ÷ 60 = 0.75. Multiply by 100 to turn it into a percentage: 0.75 × 100 = 75. So 45 is 75% of 60.

18 is 12% of what number?

12% is 0.12 as a decimal. If 0.12 of a number is 18, the number is 18 ÷ 0.12 = 150. Check: 12% of 150 is 0.12 × 150 = 18.

What is the percentage change from 80 to 100?

The change is 100 − 80 = 20. Divide it by the starting value: 20 ÷ 80 = 0.25, which is 25%. So going from 80 to 100 is a 25% increase.

Going back from 100 to 80 is a change of −20, and −20 ÷ 100 = −0.2, a 20% decrease. The same change of 20 is a smaller share of the bigger starting value.

Increase 250 by 8%

8% of 250 is 0.08 × 250 = 20, and 250 + 20 = 270. In one step: 250 × 1.08 = 270. To decrease 250 by 8% instead, multiply by 0.92: 250 × 0.92 = 230.

Working out percentages in your head

10%: divide by 10. 10% of 340 is 34.
5%: half of 10%. 5% of 340 is 17.
1%: divide by 100. 1% of 340 is 3.4.
50% and 25%: half and a quarter. 25% of 340 is 85.
Build the rest: 15% = 10% + 5%, so 15% of 340 is 34 + 17 = 51.
Swap the numbers: x% of y equals y% of x. 8% of 50 is the same as 50% of 8, which is 4.

Common mistakes

Forgetting to divide by 100. 15% of 200 is 0.15 × 200, not 15 × 200.
Using the wrong starting value. A percentage change is always measured against the old value, not the new one.
Expecting a rise and a fall to cancel out. 100 increased by 10% is 110, but 110 decreased by 10% is 99.
Mixing up percent and percentage points. A rate going from 5% to 7% rises by 2 percentage points, which is a 40% increase.
Adding discounts together. 10% off and then another 10% off is 19% off in total, not 20%.

Questions

How do I calculate a percentage of a number?

Divide the percentage by 100 and multiply by the number. 20% of 50 is 0.2 × 50 = 10.

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

Divide the first number by the second, then multiply by 100. 12 out of 48 is 12 ÷ 48 × 100 = 25%.

How do I calculate a percentage increase?

Subtract the old value from the new value, divide by the old value and multiply by 100. From 40 to 50 is (50 − 40) ÷ 40 × 100 = 25%.

How do I add 15% to a price?

Multiply the price by 1.15. $80 plus 15% is 80 × 1.15 = $92.

How do I take 20% off a price?

Multiply the price by 0.8. $45 minus 20% is 45 × 0.8 = $36.

Can a percentage be more than 100%?

Yes. 150% of 40 is 60, and a value that triples has increased by 200%.

Why do some answers show "≈"?

Some answers have decimals that never end, like 1 ÷ 3 = 0.333… qcalculate works with exact fractions, then rounds only for display and marks the answer with ≈. How we check our math.

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