FICA withholding is calculated by multiplying your gross pay by fixed tax rates set by the federal government
FICA has two parts: Social Security and Medicare. Social Security takes 6.2% of your gross pay up to a wage cap (which changes yearly—in 2024 it is $168,600). Medicare takes 1.45% of all your gross pay with no cap. If you earn over $200,000 as a single filer (or $250,000 married filing jointly), an additional 0.9% Medicare tax applies to income above that threshold. Your employer withholds these amounts automatically and sends them to the IRS.
The math is straightforward because the rates and wage bases are fixed by law. You do not need to estimate or adjust anything yourself—your payroll department handles it. But understanding how the numbers work helps you predict what will land in your account and catch errors if they happen.
Key Takeaways
- Social Security withholding is 6.2% of gross pay up to an annual wage cap that changes each year; Medicare is 1.45% of all gross pay with no cap.
- Your employer withholds both amounts and remits them to the IRS, so the calculation happens before you see your paycheck.
- If you earn above $200,000 (single) or $250,000 (married filing jointly), you owe an additional 0.9% Medicare tax on income above that threshold.
- Self-employed people pay both the employee and employer portions (15.3% total for Social Security and Medicare combined), calculated on Schedule SE.
How to calculate Social Security withholding
Take your gross pay for the pay period and multiply by 0.062 (which is 6.2%). This gives you the Social Security tax owed for that period. The key limit is the wage base—the maximum amount of annual income subject to Social Security tax. In 2024, that cap is $168,600. Once you have earned $168,600 in a calendar year, no more Social Security tax is withheld for the rest of that year.
Example: If you earn $5,000 in a biweekly paycheck and have not yet hit the wage cap, your Social Security withholding is $5,000 × 0.062 = $310. If you are near the end of the year and have already earned $166,000, only $2,600 of your next paycheck is subject to Social Security tax (the amount needed to reach $168,600), so you would owe $2,600 × 0.062 = $161.20 instead of the full $310.
The wage cap increases most years. The Social Security Administration announces the new cap in October for the following year. Your payroll system tracks your year-to-date earnings and stops withholding automatically once you cross the threshold.
How to calculate Medicare withholding
Medicare withholding is simpler than Social Security because there is no wage cap. Multiply your gross pay by 0.0145 (which is 1.45%) for every paycheck, regardless of how much you have earned so far in the year.
Example: A $5,000 paycheck results in $5,000 × 0.0145 = $72.50 in Medicare withholding. This applies to your first paycheck of the year and your last, with no reduction.
If your income exceeds the high-earner threshold ($200,000 for single filers, $250,000 for married filing jointly, $125,000 for married filing separately), you also owe an additional 0.9% Medicare tax on the amount above that threshold. This is withheld from your paycheck once you cross the threshold. Your employer is responsible for tracking this and withholding the extra amount.
Combined FICA calculation for a typical paycheck
Most employees see both Social Security and Medicare withheld from each paycheck. Here is how they add up:
| Component | Rate | Calculation | Example (on $5,000) |
|---|---|---|---|
| Social Security | 6.2% (up to wage cap) | Gross pay × 0.062 | $310 |
| Medicare | 1.45% | Gross pay × 0.0145 | $72.50 |
| Additional Medicare (if over threshold) | 0.9% | Amount over threshold × 0.009 | Varies |
| Total FICA | 7.65% base | Social Security + Medicare | $382.50 |
This total comes out of your gross pay before federal income tax withholding, state tax, or any deductions you choose. Your net pay is what remains after all withholdings.
What happens if you have multiple jobs
If you work more than one job, each employer withholds Social Security and Medicare based only on what they pay you. This can create a problem: you might hit the Social Security wage cap at one job, then start a second job and have Social Security withheld again, even though your combined earnings exceed the cap.
When this happens, you have overpaid Social Security tax. You claim the overpayment as a credit on your federal tax return (Form 1040) when you file. The IRS refunds the excess. You cannot ask your employer to stop withholding early just because you have another job—the withholding continues until you reach the cap at that specific employer.
Medicare tax has no wage cap, so there is no overpayment issue there. However, if your combined income from all jobs exceeds the high-earner threshold, make sure your employers are aware. You may need to adjust withholding at one job to avoid underpaying the additional 0.9% Medicare tax.
Self-employed FICA calculation
If you are self-employed, you pay both the employee and employer portions of FICA, totaling 15.3% (12.4% for Social Security, 2.9% for Medicare). You calculate this on Schedule SE, which you file with your tax return.
The calculation starts with your net self-employment income (your business income minus business expenses). You multiply this by 92.35% to account for the employer-side deduction, then apply the 15.3% rate. The Social Security portion still has the annual wage cap—in 2024, you pay Social Security tax only on the first $168,600 of net self-employment income.
You pay self-employment tax when you file your return, or you can make quarterly estimated tax payments throughout the year. Unlike W-2 employees, no one withholds this automatically from your income.
How to verify FICA withholding on your pay stub
Your pay stub shows the FICA amounts withheld for that pay period and your year-to-date totals. Look for line items labeled "Social Security Tax," "OASDI" (Old-Age, Survivors, and Disability Insurance—another name for Social Security), "Medicare Tax," or "Med Tax."
To verify the calculation is correct, take your gross pay and multiply by 0.062 for Social Security (if you have not hit the wage cap) and 0.0145 for Medicare. The amounts on your stub should match. If Social Security withholding drops to zero partway through the year, check your year-to-date earnings—you have likely reached the wage cap.
If the numbers do not match and you have not reached the wage cap, contact your payroll department. Errors are rare but do happen, and catching them early makes them easier to fix.
Frequently Asked Questions
Why does my Social Security withholding stop halfway through the year?
You have reached the annual wage cap. In 2024, once you earn $168,600, no more Social Security tax is withheld for the rest of that calendar year. This is normal and intentional. Your Medicare withholding continues because Medicare has no wage cap.
Can I reduce my FICA withholding?
No. FICA rates and wage bases are set by federal law and apply to all employees. You cannot adjust them on a W-4 form or ask your employer to withhold less. The only exception is if you are self-employed and underpay through estimated taxes, but you will owe the full amount when you file your return.
What if I worked in two states—do I pay FICA twice?
No. FICA is federal tax, not state tax. You pay it once based on your total income, regardless of how many states you worked in. However, state income tax rules vary by state, and you may owe tax to multiple states if you worked in more than one.
Do I get back the FICA I paid if I did not earn enough to owe federal income tax?
No. FICA is separate from federal income tax. You pay FICA on almost all wages, even if your income is too low to owe federal income tax. The only exception is if you overpaid Social Security tax due to multiple jobs, in which case you claim a credit on your return.
How do I know if the additional 0.9% Medicare tax applies to me?
The threshold is $200,000 for single filers, $250,000 for married filing jointly, and $125,000 for married filing separately. If your wages from all jobs combined exceed these amounts, your employer should withhold the extra 0.9% once you cross the threshold. If you have multiple employers, verify that at least one of them is withholding it.