The Schedule C (or Schedule C-EZ) calculates your net profit from self-employment. You must include this as income on your 1040 and use it on Schedule SE to calculate your self-employment tax. Your net profit is equal to the gross revenue you earned minus all deductible business expenses you incurred. The lower your net profit number is, the lower your self-employment tax bill will be.
Therefore, you should be extremely thorough when preparing your Schedule C to ensure you deduct every possible business expense. These expenses need to be ordinary and necessary to operate your business to qualify as deductible. They cannot be personal in nature. Common types of deductible business expenses include office rent, the cost of acquiring and maintaining a business vehicle, telephone calls, office supplies and equipment.
When you use TurboTax, you will be asked about all of your self-employment income and expenses. TurboTax will automatically use this information to calculate your self-employment tax for you.