Percentage Calculator

Quick answer A percentage is a fraction of 100: 15% of $240 is $36, from 240 times 0.15. To find what percentage 30 is of 120, divide and multiply by 100: 25%. To go backwards from a part to the whole, divide the part by its percentage as a decimal.
Quick answer: To find a percentage of a number, multiply the number by the percentage and divide by 100: 15% of 80 is 12. To find what percentage one number is of another, divide the first by the second and multiply by 100: 45 out of 60 is 75%. This page does both, plus percentage change between two values.

This percentage calculator answers the three questions that come up most often, all on one page. The first works out what a percentage of a number is, for example 15 percent of $80, which is handy for a tip, a discount, or a deposit. The second tells you what percentage one number is of another, for example what share 45 marks out of 60 represents, which is how test scores, conversion rates and progress are worked out. The third measures the percentage change from an old value to a new one, which is how price rises, pay increases, investment returns and growth are described. Percentages are simply a way of expressing a part out of one hundred, which makes very different quantities easy to compare on the same scale. Because the three calculations use the numbers in different ways, it is easy to mix them up, so each one here is laid out separately with its own answer that updates as you type. Every result is shown rounded for readability while keeping the full precision behind the scenes. Use it for shopping, schoolwork, GST checks, budgeting and any time you need a quick, reliable percentage without reaching for a formula.

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What is a percentage of a number?

%
12

X is what percentage of Y?

75%

Percentage change from old to new

+25% increase

How it works

To find a percentage of a number, multiply the number by the percentage and divide by 100. To find what percentage one number is of another, divide the first by the second and multiply by 100. To find percentage change, subtract the old value from the new, divide by the old value, and multiply by 100, where a positive result is an increase and a negative result is a decrease.

Worked example

A jacket marked $80 has 15 percent off, so the saving is $12 and you pay $68. If you scored 45 out of 60 in a test, that is 75 percent. If your rent rose from $200 to $250 a week, that is a 25 percent increase.

Who this calculator is for

This calculator is for students, shoppers and anyone working out a percentage of a number, a percentage increase or decrease, or what one number is as a percentage of another.

What this calculator assumes

  • The numbers you enter.
  • Standard percentage arithmetic.
  • Results are rounded for display.
  • It does not apply tax, discounts or product-specific rounding unless you build them into the inputs.

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Frequently asked questions

How do I find a percentage of a number?

Multiply the number by the percentage and divide by 100. For example, 15 percent of 80 is 80 times 15 divided by 100, which is 12. The first calculator here does this for you as you type.

How do I work out what percentage one number is of another?

Divide the first number by the second and multiply by 100. For example, 45 out of 60 is 45 divided by 60 times 100, which is 75 percent. The second calculator does this.

How do I calculate percentage change?

Subtract the old value from the new value, divide by the old value, and multiply by 100. A positive answer is an increase and a negative answer is a decrease. The third calculator does this.