A business' total revenue may be made up of several different departments. As an simplified example, revenue may be generated from both the sales and service departments of a company. Although total revenue gives you an overall snapshot of sales, it doesn't tell you what department generated the majority of this revenue. Calculating each department's percentage contribution to the total revenue gives you a better idea of each department's performance.
Look at the company's balance sheet for total revenues and its breakdown for each department. For example, assume the company had total revenues of $500,000, $400,000 of which was produced by the sales department, while the service department contributed $100,000.
Divide each department's revenue by the total revenue. In the example, the sales department's $400,000 is divided by $500,000 to produce 0.80. Likewise, the service department's $100,000 is divided by $500,000 to produce 0.20.
Multiply these figures by 100 to convert them into percentage format. In the example, the sales department generated 80 percent of the total revenue, while the service department only contributed 20 percent.