Self-employment tax is calculated on Schedule SE, which is filed in conjunction with Schedule C. To calculate self-employment tax, you need to determine your net profit from Schedule C, which is your total business income minus deductible business expenses. You then multiply your net profit by the self-employment tax rate, which is currently 15.3% (12.4% for Social Security and 2.9% for Medicare). However, there is a deduction available for the employer-equivalent portion of the self-employment tax. The resulting self-employment tax amount is reported on Schedule SE and contributes to your overall tax liability. It is recommended to consult with a tax professional or review the IRS guidelines to ensure accurate calculation and reporting of self-employment tax.