FICA is the name on an American payslip for two separate taxes collected together under the Federal Insurance Contributions Act. Employees pay Social Security at 6.2% and Medicare at 1.45%, a total of 7.65%, and the employer pays the same again, according to the IRS. Combined, the job carries 15.3% before income tax is counted.
The two halves behave differently at the top. Social Security stops at the wage base, $184,500 of earnings in 2026; Medicare has no ceiling. Above $200,000 of wages from one employer in a calendar year, a further 0.9% is withheld with no employer match, and the threshold that finally applies on your return depends on filing status, per IRS Topic 560.
That cap makes FICA regressive at high pay. On $75,000 you pay $5,737.50, the full 7.65%. On $250,000 as a single filer you pay $11,439 of Social Security, $3,625 of Medicare and $450 of the additional tax, $15,514 in all, which is only about 6.2% of your wages.
FICA is not income tax. It is charged on wages from the first dollar, with no standard deduction and no brackets beyond the cap and the additional threshold, so someone who owes no federal income tax at all can still pay it in full. That is why the effective rate on a modest salary is often driven more by FICA than by the income tax bands.
The take-home pay calculator charges both parts on gross pay, applies the wage base and the additional Medicare threshold for the filing status you choose, and shows the employer's matching share in the total cost to employer.