Calculate Percentage


Percentage from two values


Percentage of increase/decrease values


Calculating the Percentage

Determine what a percentage represents. A percentage is an expression of part of the whole. 0% represents nothing, and 100% represents the entire amount. Everything else is somewhere in between!

For example, say you have 10 mangos. If you eat 2 mangos, then you have eaten 2 out of the whole 10 mangos (2 / 10 × 100% = 20% eaten). If 10 mangos is 100% and you ate 20%, then 100% - 20% = 80% of the mangos remain.

Calculate the value of the whole. In some cases, you will be given the value for part of the whole and the whole. Other times, you might get two parts that make up the whole. It is important to distinguish what the percentage is "of." For instance, let's say we have a jar containing 1199 red marbles and 485 blue marbles, making it 1684 marbles in total. In this case, 1684 makes up a whole jar of marbles, that is 100%.

Find the value that you want to turn into a percentage. Let's say we want to find out the percentage of the jar that is taken up by the blue marbles. Then the percentage of the whole we are looking for is 485 (the number of blue marbles) of 1684 (the whole amount).

Put the two values into a fraction. The part goes on top of the fraction (numerator), and the whole goes on the bottom (denominator). Therefore the fraction in this case is 485/1684 (part/whole)

When you're setting up two proportions, it's easiest to set them both up as the part over the whole on either side of the equation.

Convert the fraction into a decimal. Percentages are best calculated from the decimal form. To turn 485/1684 into a decimal, divide 485 by 1684 using a calculator or pencil and paper. This comes to 0.288

Convert the decimal into a percent. Multiply the result obtained in the step above by 100% (per 100 = per cent). For this example, 0.288 multiplied by 100% equals 28.8%