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Percentage Calculator

Work out percentages, percentage change and percent of a number.

Percent of a number

What is % of ?

What percent one number is of another

is what % of ?

Percentage increase or decrease

From to

Add or subtract a percentage

%

When to use it

The percentage calculator answers the four everyday percentage questions without formulas: working out a discount or a tip, checking a pay rise, comparing prices, marking a test, splitting a bill, or understanding statistics in the news. Each question has its own row, and the answer updates as you type.

How to use it

The page has four calculators. Type in any row; you don’t need to press a button.

  1. Percent of a number: “What is 20 % of 150?” Use it for discounts, tips, commission and tax amounts.
  2. What percent one number is of another: “30 is what % of 120?” Use it for test scores, survey results and progress toward a goal.
  3. Percentage increase or decrease: “From 80 to 100”. Use it for price changes, salary rises, growth and losses.
  4. Add or subtract a percentage: “250 plus or minus 15 %”. Use it for prices with tax, discounted prices, and markups.

Choose plus or minus in the fourth row. Results show up to six decimal places, so round them as you need.

A worked example

A jacket was $80 and is now $100. What happened, and what will it cost on sale?

  • In Percentage increase or decrease, enter from 80 to 100: an increase of 25% (+20).
  • The shop then offers 15% off. In Add or subtract a percentage, enter 100, choose minus, and enter 15: = 85.
  • Did you score well on a 120-question test with 96 right? In row two, 96 is what % of 120: 80%.

Handy shortcuts

  • 10% of any number: move the decimal point one place left (10% of 64 = 6.4).
  • 5% is half of 10%; 20% is double 10%.
  • Reverse a percentage: if a price after a 20% discount is $64, the original was 64 ÷ 0.8 = $80.
  • Percentages swap: 8% of 50 equals 50% of 8. Pick whichever is easier.

Common mistakes

  • Using the wrong starting value for a change. A change from 80 to 100 is +25%, but from 100 to 80 is −20%. Always divide by the starting value.
  • Adding percentages in a row. Two 10% rises are 21% in total, not 20%, because the second applies to the higher amount.
  • Confusing “of” and “off”. 15% of 100 is 15; 15% off 100 is 85.
  • Starting from zero. A percentage change from 0 can’t be calculated; the tool tells you so.

Work out shop savings with the Discount Calculator, add tax with the VAT and Sales Tax Calculator, or split a restaurant bill with the Tip Calculator.

Frequently asked questions

How do I work out a percentage of a number by hand?

Divide the percentage by 100 and multiply by the number. For 20% of 150, that's 0.2 × 150 = 30.

Why isn't a 50% rise followed by a 50% fall back to the start?

Because the second percentage is taken from a different, bigger number. 100 plus 50% is 150, and 150 minus 50% is 75. To undo a 50% rise you need a fall of about 33.3%.

What's the difference between percent and percentage points?

If an interest rate goes from 4% to 5%, it has risen by 1 percentage point but by 25 percent (because 1 is a quarter of 4). News reports often mix these up.

Can I use decimals and negative numbers?

Yes. Type decimals with a point, such as 12.5. Negative numbers work for changes, for example a profit going from -200 to 300.

How do I add VAT or sales tax?

Use "Add or subtract a percentage" with plus and your tax rate. For full tax breakdowns, including taking tax out of a price, use the VAT and Sales Tax Calculator.

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