How to Calculate a Quantity Based on the Percent Given

Decimal

• 1

  Convert a percent into a decimal to determine the quantity indicated.

• 2

  Move the decimal point after a percent two spots to the left. For example, if you are attempting to deduce a quantity based on 20 percent, you are left with .20 after moving the decimal point, while 150 percent translates to 1.50 and 78.4 percent to .784.

• 3

  Multiply the decimal by the total number of which the percent is a part. For example, to find 20 percent of 115, multiply .20 by 115, resulting in a quantity of 23. You can practice long-hand multiplication or use a calculator.

Fraction

• 4

  Translate a percentage into a fraction. Since percentage indicates a fraction over 100, 20 percent would be represented as 20/100.

• 5

  Convert the total number of which the percent is a part into a fraction as well. For example, if you are trying to find 20 percent of 6, represent 6 as 6/1.

• 6

  Multiply the two fractions. For example, 20/100 x 6/1 = 120/100. Divide the numerator (top number) by the denominator (bottom number) to find the quantity, which in this case equals 1.20 or 6/5.