An employee pays 7.65% of wages toward federal retirement taxes and the employer matches that amount, so the federal government receives an amount equal to 15.3% of wages for Social Security and Medicare. However, a self-employed person pays both the individual 7.56% portion and the 7.65% employer portion. In this manner, the self-employed person pays more in tax than an employee.
The Social Security and Medicare taxes (aka FICA) are not income taxes. As for income taxes, the self-employed individual pays the same income tax rate as an employee. However, since self-employed persons do not have tax withholding as do employees, whose employers subtract tax before paying a net wage, tax impacts are generally more apparent to the self-employed person. Whereas the employee has taxes withheld out of every paycheck, the self-employed person makes a quarterly estimation and payment of taxes.