What is FICA? The Federal Insurance Contributions Act is the federal law that requires you to withhold two separate taxes from the wages you earn. It includes Social Security Tax and Medicare Tax at a flat percentage rate. The Social Security Tax is 6.2% rate of your wages, and the Medicare Tax is 1.45% of your wages. If you earn more than $200,000, you will also be taxed an additional 0.9% Medicare surtax. Youâre not the only one paying for FICA, however.