How FICA Is Calculated on Biweekly Pay

What FICA is

FICA stands for the Federal Insurance Contributions Act. It is made up of two separate taxes. The first is Social Security, which funds retirement, disability, and survivor benefits. The second is Medicare, which funds hospital insurance for people aged 65 and older and some younger people with disabilities. Both are taken out of your gross pay before you see your paycheck, and your employer pays a matching amount on top of what you pay.

FICA is separate from federal income tax. Income tax depends on your filing status, your deductions, and your tax bracket. FICA is a flat percentage of your wages, and it does not change based on whether you are single or married.

2026 FICA rates and limits

Together, the employee share of Social Security and Medicare is 7.65% of your wages, up to the Social Security cap. The most Social Security tax an employee can pay in 2026 is $11,439.00, which is 6.2% of the $184,500 wage base.

The formula for one biweekly paycheck

For a typical paycheck, the calculation takes three steps:

1. Start with your FICA wages for the pay period. This is usually your gross pay, minus a few types of pre-tax deductions explained below.
2. Multiply by 6.2% to get the Social Security tax, as long as you have not yet reached the annual cap.
3. Multiply by 1.45% to get the Medicare tax, which applies to every paycheck all year.

Add the two amounts together and you have the FICA withholding for that paycheck. Many pay stubs list them as separate lines, often labeled OASDI (or Social Security) and Medicare.

Worked example: $78,000 salary, paid biweekly

A $78,000 annual salary paid every two weeks works out to $3,000 per paycheck ($78,000 divided by 26). Assuming all of that is FICA wages, each paycheck is taxed like this:

• Social Security: 6.2% of $3,000.00 = $186.00
• Medicare: 1.45% of $3,000.00 = $43.50
• Total FICA per paycheck: $229.50

Over 26 paychecks, that is $5,967.00 for the year, which is exactly 7.65% of $78,000. This salary is well below the Social Security cap, so the same amounts come out of every paycheck from the first one in January to the last one in December.

What happens when you reach the Social Security cap

Social Security tax only applies to wages up to the annual wage base, which is $184,500 for 2026. Once your year-to-date wages pass that amount, your employer stops withholding Social Security tax for the rest of the year, and your take-home pay goes up. Medicare has no cap, so it keeps being withheld on every paycheck.

For example, someone earning $250,000 a year and paid biweekly gets about $9,615 per paycheck. Social Security tax is withheld on each paycheck until the year-to-date total reaches $184,500, which happens partway through the 20th paycheck. The final Social Security withholding that period is only on the part of the paycheck that fits under the cap, and the remaining paychecks of the year have no Social Security tax at all.

That is why high earners often notice a larger paycheck late in the year. It is not a raise. It is the Social Security tax stopping.

The Additional Medicare Tax

Employers must withhold an extra 0.9% Medicare tax on wages they pay you above $200,000 in a calendar year. This applies no matter your filing status, and your employer does not match it. Continuing the $250,000 example for the full year:

• Social Security: capped at $11,439.00
• Medicare: 1.45% of $250,000 = $3,625.00
• Additional Medicare Tax: 0.9% of the $50,000 above $200,000 = $450.00
• Total FICA for the year: $15,514.00

The thresholds on your actual tax return are different for married couples filing jointly ($250,000) and married filing separately ($125,000), so the amount withheld from your paycheck can differ slightly from what you owe when you file.

Which deductions reduce your FICA wages

Not every pre-tax deduction lowers your FICA tax. The difference matters when you compare your pay stub with a calculation.

• Traditional 401(k) contributions reduce your income tax wages but not your FICA wages, so FICA is still calculated on the full amount.
• Health insurance premiums paid through an employer cafeteria plan (Section 125) generally reduce both income tax wages and FICA wages.
• Health savings account contributions made through payroll under a cafeteria plan are also generally exempt from FICA.

If your numbers do not match your stub, check these deductions first, and confirm the details with your payroll department.

Biweekly, semimonthly, and weekly pay

The pay schedule changes how much is withheld on each paycheck, but not the yearly total. Biweekly pay means 26 paychecks, semimonthly means 24, and weekly means 52. The 7.65% rate is applied to each one, so a biweekly paycheck is smaller than a semimonthly paycheck for the same salary, and the annual FICA amount comes out the same. Self-employed workers pay both halves themselves, a combined 15.3% on net earnings, through self-employment tax instead of payroll withholding.

See your own numbers

Our calculator applies FICA, federal income tax, and your state rules to your actual salary, so you can see each deduction on your own paycheck. For a deeper look at income tax, read our 2026 federal tax brackets guide.