Fraction to Percentage

A fraction and a percentage describe the same thing in two different languages: both say how big a part is compared with a whole. This converter takes the numerator (the top number) and the denominator (the bottom number) and gives you the equivalent percentage and decimal as you type.

The formula

To turn a fraction into a percentage, divide the numerator by the denominator and multiply the result by 100:

percentage = (numerator ÷ denominator) × 100

The division on its own gives the decimal form, and multiplying by 100 expresses it "per hundred." Take 3/8: dividing 3 by 8 gives the decimal 0.375, and multiplying by 100 gives 37.5%. The same steps work for any fraction — 1/4 is 0.25 = 25%, and 5/4 is 1.25 = 125%, which is fine because a fraction larger than one simply becomes a percentage above 100.

A worked example

Suppose a whole is divided into 8 equal parts and you hold 3 of them. As a fraction that is 3/8. To express your share as a percentage, divide 3 by 8 to get 0.375, then multiply by 100 to get 37.5%. The remaining 5 parts are 5/8 = 0.625 = 62.5%, and the two pieces add back to 100%, confirming the conversion. Checking that your parts sum to 100% is a reliable way to catch a typo in either number.

Fractions, percentages and charts

Converting fractions to percentages is often the first step toward charting them. A pie chart reads its slices as percentages of a whole, so a 3/8 share becomes a slice covering 37.5% of the circle — just over a third. Once each part of your data is expressed as a percentage, the slices are ready to draw and the whole picture sums neatly to 100%.

When your fractions are converted, send the percentages to the pie chart maker to build a pie or donut, or open make a chart to compare them as bars instead. To go the other way and take a percentage of a number, use the percentage of tool.