Percent to Decimal Calculator

How to convert a percentage to a decimal

A percentage is a number out of one hundred, so turning it into a decimal means dividing by 100. In practice that is the same as sliding the decimal point two places to the left and dropping the percent sign.

decimal = percent ÷ 100

1. Write the percentage without its % sign, for example 45.
2. Divide by 100, or move the decimal point two places to the left: 45 becomes 0.45.
3. If the number is short of digits, pad with zeros as you move the point: 3% becomes 0.03, and 0.8% becomes 0.008.

The rule works for every real number. Percentages above 100 give decimals above 1 (250% is 2.5), and a negative percentage gives a negative decimal (−12% is −0.12).

Using the calculator

Enter the percentage in the box, with a dot as the decimal mark, and press Convert to Decimal. The answer appears as "Decimal number".

• The result is rounded to four decimal places, so 7.5% is displayed as 0.0750 and 33.333333% as 0.3333.
• Whole results are shown without decimals (100% gives 1), and a result with one or two decimals is shown with two (250% gives 2.50).
• Very small results can round to nothing: 0.000123456% is 0.00000123456, which is displayed as 0. Work those out by hand if you need every digit.
• Large results use commas: 5,000,000% is shown as 50,000.

Worked examples

• 45% → 0.45. Move the point two places left.
• 7.5% → 0.075. 7.5 ÷ 100 = 0.075.
• 0.8% → 0.008. Less than one percent is a decimal below 0.01.
• 250% → 2.5. More than 100% is more than 1.
• −12% → −0.12. The sign carries over unchanged.

Decimals are what you need before multiplying. A sales tax of 6.25% on an 80 purchase is 80 × 0.0625 = 5.00, and 4.5% yearly interest on a 2,000 balance is 2,000 × 0.045 = 90. Typing 4.5% directly into a spreadsheet formula without converting it is a classic way to get an answer that is out by a factor of 100.

Percent to decimal conversion table

Why convert to a decimal first?

Percentages are convenient to read, but arithmetic is done with decimals. Spreadsheets store a cell formatted as 45% as the number 0.45, and most programming languages have no percent type at all, so a rate has to be a decimal before it can be multiplied.

Decimals also give you the growth and shrink multipliers directly. To raise 120 by 15%, multiply by 1 + 0.15 = 1.15 and get 138. To lower it by 15%, multiply by 1 − 0.15 = 0.85 and get 102. And a tip of 18% on a 350 bill is 350 × 0.18 = 63. For many percentage questions at once, the percentage calculator does the conversion for you.

Common mistakes

• Moving the point only one place: 5% is 0.05, not 0.5.
• Confusing 0.5% with 50%. Half a percent is 0.005, while fifty percent is 0.5.
• Moving the point the wrong way when going back. To turn a decimal into a percentage you multiply by 100, which moves the point two places to the right.
• Leaving the % sign in a calculation, where it can be read as an operator by a spreadsheet or calculator.

To go the other way, use the decimal to percent calculator. If you need a fraction instead, try the percent to fraction calculator, and for percentages of a number the percentage calculator handles the whole calculation in one step. The same conversion is also available as a live tool in the percent to decimal converter.