How to Work Out the Percentages for a Pie Chart
- 1). Start by getting the sum total of all the data. For example, we'll use the following data from the construction industry obtained from the Department of Labor Statistics: carpenters, 805,410; construction laborers, 836,420; construction managers, 179,900; electricians, 477,540; and other equipment operators, 273,050. For this data, the total is 2,572,320.
- 2). Divide the value for each category by the final total to get the percentage for that category in decimal form. Multiply the decimal form by 100 to get the percentage form.
Carpenters: 805,410/2,572,320 = 0.313 x 100 = 31.3 percent
Construction laborers: 836,420/2,572,320 = 0.325 x 100 = 32.5 percent
Construction managers: 179,900/2,572,320 = 0.070 x 100 = 7.0 percent
Electricians: 477,540/2,572,320 = 0.186 x 100 = 18.6 percent
Other equipment operators: 273,050/2,572,320 = 0.106 x 100 = 10.6 percent - 3). Make sure the percentages total 100. If they don't, rework the calculations to find the error. (31.3 + 32.5 + 7.0 + 18.6 +10.6 = 100)
- 4). Use the percentages to calculate the angles necessary to draw the pie chart.