FICA is the acronym for Federal Insurance Contributions Act. It generally requires employers to withhold Social Security and Medicare taxes from their employees' earnings (wages, salaries, commissions, bonuses, etc.) and then match the amounts withheld. This means that employers must remit to the government two times the amount withheld from their employees for Social Security and Medicare taxes.
For example, if an employer has only one employee earning $30,000 per year, the employer must withhold $2,295 of FICA tax from the employee. (6.2% for the Social Security tax of $1,860, plus 1.45% for the Medicare tax of $435.) The employer must then match the $2,295 and remit the total of $4,590 to the federal government.
The employer's cost of matching the FICA taxes (the matching amounts for the Social Security tax and Medicare tax) is recorded by the employer as an additional expense or manufacturing cost.
You can find the rules for FICA taxes in the Internal Revenue Service Publication 15 (Circular E) Employer's Tax Guide at its website www.irs.gov.