Net income is a number you want to monitor for stability or growth. Depending on the company and what they are doing, that number can drop but it should be for reasons such as acquisitions or new equipment. To calculate net income, you will take the company?s whole revenue number and subtract business expenses and operating costs to get a number pre tax. From there you can take out taxes and arrive at the net income number. Taxes are important to watch as well as you want to see favorable tax numbers over the long haul.