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Percentage calculator

Choose what you want to know and enter two numbers: the answer and the working appear straight away. Handy for discounts, pay rises, test scores, interest or growth.

What do you want to know?

Without the % sign; 12.5 works too.

Fill in the fields; the answer appears here straight away.

How it works

  1. Enter the values

    Type the numbers or the formula. Decimals may use a point or a comma. No idea? Click Fill in an example.

  2. Instant answer

    The answer appears as you type, with the most important intermediate values.

  3. See the working

    Under "How it's worked out" you see the steps, handy for checking your own calculation.

Five ways to calculate with percentages

  • X% of a number: 15% of 80 is 0.15 × 80 = 12.
  • What percentage is it? 30 out of 120 is 30 ÷ 120 × 100 = 25%.
  • Percentage change: from 80 to 60 is (60 − 80) ÷ 80 × 100 = −25%, a decrease of 25%.
  • Number plus X%: 200 plus 10% is 200 × 1.10 = 220.
  • Number minus X% (discount): 49.95 with 20% off is 49.95 × 0.80 = 39.96.

Adding and removing the same percentage

Adding 10% and then taking 10% off doesn't bring you back to the start: 100 becomes 110 and then 99. The second 10% is taken from a bigger number. To find what an amount was before an increase, divide by the factor instead: 110 ÷ 1.10 = 100. For VAT, the VAT calculator does this for you.

Percent or percentage point?

If an interest rate goes from 2% to 3%, that is a rise of 1 percentage point, but of 50 percent (because 1 is half of 2). Choose Percentage change to work out the second one.

Worked examples

  • A pay rise: from 2,400 to 2,550 is (2,550 − 2,400) ÷ 2,400 × 100 = 6.25% more.
  • A discount: 129 with 15% off is 129 × 0.85 = 109.65, so you save 19.35.
  • A tip: 12% of 48.50 is 0.12 × 48.50 = 5.82.
  • A test score: 34 correct answers out of 40 is 34 ÷ 40 × 100 = 85%.

Finding the original number

The calculator works forwards. To go back, divide by the factor. A jacket costs 80 after 20% off, so it used to cost 80 ÷ 0.80 = 100, not 80 + 20% = 96. The same goes for a number that went up: 138 after a 15% increase was 138 ÷ 1.15 = 120.

Why 50% up and 50% down is not zero

100 plus 50% is 150, and 150 minus 50% is 75, not 100. A percentage always refers to the number it is applied to. The same trap hides in "up 10% two years in a row", which is 21% in total (1.10 × 1.10 = 1.21), not 20%. For growth over many periods use the exponential growth calculator or the compound interest calculator.

Frequently asked questions

How do I calculate 20% of a number?

Multiply by 0.20, or divide by 5. 20% of 65 is 0.20 × 65 = 13. Choose *X% of a number*, enter 20 and 65, and the working appears below the answer.

How do I work out a percentage increase or decrease?

Choose *Percentage change* and enter the old and the new value. The result is (new − old) ÷ old × 100, so a positive answer is an increase and a negative answer a decrease.

Can I type 12,5 or 12.5?

Yes, both mean twelve and a half. Enter the percentage without the % sign, with a comma or a point as the decimal separator.

What is the difference between a percentage and a percentage point?

Going from 2% to 3% is 1 percentage point, but a rise of 50 percent, because the change is measured against the old value. *Percentage change* gives you the second number.