Using percentages to represent changes in quantified items, such as sales, losses, market share, and take rate, is an easy way to explain changes to people who may not be mathematically-minded. Determining the percentage of something is relatively straightforward and what the percentage will represent is entirely up to you. To determine and use a percentage will require you to do some light math. You will also need a set of at least two numerical figures that represent the same thing, for example, the total number of units sold in the first year and the total number of units sold in the second year.

Note the first set of numbers as well as the second set. For this example, we will compare sales of units between two different sales years. In the first year, 25 of 50 units were sold and in the second year, 35 of 50 units were sold.

Subtract the two numbers so that you have the numerical difference between the two sets. In this example, the difference is 10 units.

Multiply the difference by 100, which is the highest percentage that can be achieved. In this example, we will multiply 10 times 100 which yields 1,000.

Divide the result of step 3 by the total number of units that could have been sold, which in this case is 50. Following our example, this gives a result of 20, which we can interpret as 20 percent. We can say that the business used in the example had a sales increase of 20 percent from its first to second year.