Taxpayers who are self-employed must pay self-employment tax on their income from self-employment. The self-employment tax applies in lieu of Federal Insurance Contributions Act (FICA) taxes paid by employees and employers on compensation from employment. Like FICA taxes, the self-employment tax consists of taxes collected for Social Security and for Medicare (hospital insurance or HI).

The self-employment tax is levied and collected as part of the income tax. The tax must be taken into account in determining an individual’s estimated taxes. The self-employed taxpayer is responsible for the self-employment tax, in effect paying both the employer’s and the employee’s share of the tax. The tax is calculated on Schedule SE, filed with the individual’s income tax return, and is then reported on the Form 1040.

Self-Employment Tax Rate

The self-employment tax rate is 15.3 percent of self-employment income. This is the same overall percentage that applies to an employee’s compensation. The rate combines the 12.4 percent Social Security tax and the 2.9 percent Medicare tax. Self-employed individuals can deduct one-half of the self-employment tax. (For 2011 and 2012, the Social Security tax rate was reduced from 12.4 to 10.4 percent.) If the individual’s net earnings from self-employment are less than $400 (or $100 for a church employee), the individual does not owe self-employment tax.

Like FICA taxes, the 12.4 percent Social Security tax only applies to earning up to a specified threshold. For 2013, this threshold was $113,700; for 2014, the threshold is $117,000. There is no ceiling for applying the 2.9 percent Medicare tax.

Self-Employment

The tax applies to net earnings from self-employment. This is the taxpayer’s gross income for the year from operating a trade or business, minus the deductions allowable to the trade or business, plus the taxpayer’s distributive share of income or loss from a partnership.

A person is self-employed if he or she carries on a trade or business as a sole proprietor or independent contractor. A general partner of a partnership that carries on a trade or business is also considered to be self-employed. Self-employment does not include the performance of services by an employee. However, an employee who also carries on a separate business part-time can be self-employed with respect to the business.

Additional Medicare Tax

Effective for 2013 and subsequent years, both employees and self-employed individuals must pay an additional 0.9 percent Medicare tax if their FICA wages or self-employment income exceeds specified thresholds $250,000 for joint filers; $125,000 for married filing separately; and $200,000 for all other taxpayers. This tax is determined on Form 8959.