How to Calculate Percentages

This article provides a straightforward explanation of how to change a fraction to a decimal and decimals and fractions to percents.

Steps [edit]

Put the fraction in lowest terms. This means that if the numerator and the denominator have a common factor, you should divide them both by the same number: for example, 3/6 = 1/2.
Divide the numerator by the denominator. So if your fraction is 1/2 you divide 1 by 2. If you don't have a calculator, the 1 goes in the box.

Change the decimal to a percent. Once you have your decimal, you can change it into a percent. To do this, simply move the decimal point over two spaces to the right and add a percent sign. (for example, 0.5 = 50%).

Divide 100 by the denominator.
Multiply the numerator by this number. This is the percentage. For example, for 4/5: 100 ÷ 5 = 20; 20 X 4 = 80%.

Lowest terms = Simplest form
Numerator = Top number in a fraction
Denominator = Bottom number in a fraction
Common factor = A number that can be divided into two numbers evenly
Percentages are very handy for expressing a portion of a whole. The whole is represented by 100%. Example: Suppose you have 10 apples. 10 apples is 100% of the apples that you have. If you eat 2 apples, then you have 80% of your original apples and you have eaten 20% of them.
A visual representation of what percentage means can be shown with pie charts. A complete pie represents 100%. Pieces of the pie represent percentages of the whole pie that are less than 100% or the whole pie. An example of this can be seen at Make A Pie Graph.

Make sure you move the decimal to the right, not the left.
Make sure you move the decimal point two spaces. For example, 0.375 = 37.5% not 375%. Likewise, 0.2 = 20% not 2%.