Self-employment taxes consist of
12.4% for Social Security. For 2016, this part of the tax applies to the first $118,500 of earnings. If you earn more than that (from self-employment or, if you also have a job, from the combination of your job and your business), then the 12.4 percent part of the tax that pays for Social Security stops for the year.
AND
2.9% for Medicare. The Medicare portion of the self-employment tax doesn’t stop. No matter how much you earn, you'll pay the 2.9 percent Medicare tax.
