To calculate Social Security tax, multiply your taxable earnings by 6.2% if you’re a W-2 employee, or by 12.4% on 92.35% of your net profit if you’re self-employed. The tax only applies to earnings up to $184,500 in 2026, so the most any employee will pay this year is $11,439.1Social Security Administration. Contribution and Benefit Base Everything above that ceiling is free of the 6.2% tax, though Medicare tax keeps going.
The Two Numbers That Drive the Calculation
The employee rate is 6.2%, set by the Federal Insurance Contributions Act and unchanged since 1990.2Office of the Law Revision Counsel. 26 USC 3101 – Rate of Tax Your employer pays a matching 6.2% on top of your wages, so 12.4% total flows to the Social Security trust funds on every covered dollar.3Office of the Law Revision Counsel. 26 USC 3111 – Rate of Tax
The wage base limit is what changes each year. The Social Security Administration indexes it to the national average wage index, which tracks overall wage growth.4Social Security Administration. National Average Wage Index For 2026, the taxable maximum is $184,500, up from $176,100 in 2025.1Social Security Administration. Contribution and Benefit Base Once your year-to-date earnings cross that line, Social Security withholding stops for the rest of the year.
What Counts as Taxable Wages
Federal law defines wages broadly: all pay for work, cash and the cash value of non-cash compensation.5Office of the Law Revision Counsel. 26 USC 3121 – Definitions Salary, hourly pay, bonuses, and commissions all count. So do tips: if you receive $20 or more in tips during any calendar month, your employer must withhold Social Security tax on them.6Internal Revenue Service. Topic No. 761, Tips – Withholding and Reporting
A few employer-sponsored benefits come out before the tax is figured. Health insurance premiums paid through a Section 125 cafeteria plan are the big one; when your employer deducts those premiums pre-tax, they’re not subject to Social Security or Medicare tax.7Internal Revenue Service. FAQs for Government Entities Regarding Cafeteria Plans Dependent care assistance up to $5,000 and HSA contributions run through a cafeteria plan get the same treatment.
A common trap: 401(k) contributions don’t reduce Social Security tax. Traditional 401(k) deferrals lower your federal income tax withholding, but they stay fully subject to FICA. On your W-2, Box 1 (income-tax wages) will be smaller than Box 3 (Social Security wages) by roughly the amount you deferred. That’s not a mistake, and it works in your favor later because those earnings still count when your Social Security benefit is calculated.
Running the Numbers as an Employee
The employee calculation is three steps:
- Add up gross wages for the year: salary, bonuses, commissions, reported tips.
- Subtract Section 125 cafeteria plan deductions (health insurance, HSA, dependent care). Do not subtract 401(k) contributions.
- Multiply the result by 0.062. If the result is more than $184,500, tax only the first $184,500.
An example. You earn $95,000 in salary and put $4,000 into a cafeteria plan for health insurance. Your Social Security taxable wages are $91,000. The tax: $91,000 × 0.062 = $5,642 for the year. Your employer separately pays another $5,642 on your behalf, out of the business’s payroll budget rather than your paycheck.
A higher earner making $220,000 with no cafeteria plan deductions hits the cap. Social Security tax applies to the first $184,500 only, so the employee pays $11,439 and the employer matches it.1Social Security Administration. Contribution and Benefit Base The remaining $35,500 escapes the 6.2% tax, though Medicare still applies to the full amount.
Running the Numbers if You’re Self-Employed
When you work for yourself, there’s no employer to pay the other half. You owe the full 12.4% Social Security rate on your net self-employment earnings.8Office of the Law Revision Counsel. 26 USC 1401 – Rate of Tax Two adjustments in the tax code keep the burden roughly even with what W-2 workers pay.
Multiply Net Profit by 92.35% First
Before applying the 12.4% rate, multiply your net profit by 92.35% (100% minus 7.65%). This mirrors the fact that W-2 employees aren’t taxed on their employer’s share of FICA. So if Schedule C shows $100,000 in net profit, the Social Security tax runs on $92,350, not the full $100,000: $92,350 × 12.4% = $11,451.40. The $184,500 wage base still caps things, but it applies after the 92.35% reduction, so net profit has to top roughly $199,700 before the cap starts helping you.
Deduct Half of the Total Later
After you finish Schedule SE, half of your total self-employment tax (Social Security plus Medicare) comes off your income on Schedule 1 of Form 1040.9Internal Revenue Service. Self-Employment Tax The deduction reduces income tax; it doesn’t reduce the self-employment tax itself. It exists so self-employed workers end up in about the same place as employees, whose employers’ 6.2% never appears in taxable income to begin with.
The $400 Floor
Self-employment tax kicks in only when your net earnings reach $400 for the year. Below that, you don’t owe Social Security or Medicare on the income and don’t file Schedule SE.10Internal Revenue Service. Self-Employment Tax (Social Security and Medicare Taxes)
You calculate the tax on Schedule SE filed with your Form 1040, and you pay it in during the year through quarterly estimated payments on Form 1040-ES.11Internal Revenue Service. About Schedule SE (Form 1040), Self-Employment Tax For the 2026 tax year, the quarterly due dates are April 15, June 15, September 15, and January 15, 2027.12Taxpayer Advocate Service. Making Estimated Payments
Two Jobs and Excess Withholding
Each employer withholds Social Security tax on the wages it pays you, with no visibility into what your other employers are doing. If your combined wages from two or more jobs top $184,500, both employers keep withholding until each one’s payments to you individually reach the cap. That leaves you with too much withheld.
You get it back on your tax return. Claim the excess as a credit on Schedule 3 of Form 1040, and it either lowers your tax bill or increases your refund. The IRS figures the overage from the Social Security wages reported across your W-2s. Employers don’t get their portions refunded, because each employer’s obligation is calculated separately on the wages it paid.13Office of the Law Revision Counsel. 26 USC 3121 – Definitions
Don’t Forget Medicare
Your pay stub’s FICA line usually bundles two taxes. Medicare is the other one, at 1.45% for employees and 1.45% for employers.2Office of the Law Revision Counsel. 26 USC 3101 – Rate of Tax There’s no wage base on Medicare. Every dollar you earn gets the 1.45% rate. So combined FICA withholding is 7.65% on wages up to $184,500 and 1.45% on wages above it.14Social Security Administration. 2026 Cost-of-Living Adjustment (COLA) Fact Sheet
High earners owe an extra 0.9% Additional Medicare Tax on wages above $200,000 for single filers, $250,000 for joint filers, or $125,000 for married filing separately.15Office of the Law Revision Counsel. 26 US Code 3101 – Rate of Tax The employee pays this one alone; there’s no employer match. Self-employed workers owe an equivalent version under a parallel provision. These thresholds aren’t indexed for inflation.
One boundary worth naming: a handful of narrow groups are exempt from Social Security tax, including members of certain recognized religious sects who file Form 4029 and waive future benefits, and employees of foreign governments or international organizations working in the U.S.16Social Security Administration. Are Members of Religious Groups Exempt From Paying Social Security Taxes17Internal Revenue Service. Employees of a Foreign Government or International Organization (FICA) For everyone else, there’s no income-based opt-out and no general hardship exemption; the calculation above is the calculation.