To convert a whole number to a percentage, divide the whole number by the total number of objects in the group. Multiply by 100, and round to the necessary number of decimal places.
- Change whole numbers to fractions
Turn the whole number into a fraction by putting it over the total number of objects. For example, if there are 25 balls and 20 of them are green, then the fraction would be 20/25.
- Change the fraction into a decimal
Divide the whole number, which is the number on top, by the total number, or the number on the bottom to get a decimal. From the previous example, 20/25 would be 20 divided by 25, which is 0.8 as a decimal.
- Change the decimal to a percent
To change decimal to percentage, multiply the decimal by 100, or move the decimal point two places to the right. From step two, the decimal is 0.8, so multiply this number by 100. The percentage is 80 percent.
- Round the number, if necessary
Round the percentage, depending on the number of decimal places required. For example, if the percentage is 20.345 and must be rounded to two decimal places, then the answer would be 20.35.