IRC Section 3121: FICA Wages, Exclusions, and 2026 Wage Base

Under Internal Revenue Code Section 3121, FICA wages include essentially all compensation an employer pays an employee, in cash or in any other form, unless a specific statutory exclusion applies. That single default rule drives every Social Security and Medicare tax calculation on a paycheck. For 2026, FICA wages are subject to Social Security tax up to a wage base of $184,500, and to Medicare tax with no cap at all.

The Default: Nearly Everything Is a FICA Wage

Section 3121 opens with an intentionally broad sweep. FICA wages include “all remuneration for employment, including the cash value of all remuneration paid in any medium other than cash.”¹ Salaries, hourly pay, commissions, bonuses, vacation and sick pay, severance, and dismissal pay all fit. The payment doesn’t need to be tied to active work: amounts paid because the employment relationship exists, including payments for not working, still count.

The “cash value” language pulls in non-monetary compensation as well. Goods, lodging, meals, and stock options are valued at fair market value and treated as FICA wages. The spread between the exercise price and fair market value when a nonqualified stock option is exercised is a common example.

Because the default is so broad, any item of compensation is presumed taxable for FICA unless you can point to a specific exclusion in the statute. That presumption also runs independently of the income tax withholding rules. A payment can be exempt from income tax withholding yet fully subject to FICA, or the other way around.

What Section 3121 Excludes

The statute carves out specific categories of payments. Each exclusion carries conditions, and a payment escapes FICA only when every condition is met.

Qualified Retirement Plan Contributions

Employer contributions to a tax-exempt trust under a qualified plan, such as an employer match to a 401(k), are excluded from FICA wages. Payments to a simplified employee pension are also excluded, other than certain salary reduction contributions.¹

This is where payroll processing sometimes goes wrong. An employee’s own elective deferrals into a 401(k) reduce income tax withholding, but they remain fully subject to FICA. The statute explicitly keeps elective deferrals inside the FICA wage base. The employer match is out; the employee’s pre-tax contribution is not.

Health-Related Benefits

Employer payments for medical or hospitalization expenses connected to sickness or disability are excluded, whether paid directly to the employee or to an insurance carrier on the employee’s behalf.² Employer-paid health insurance premiums and Health Savings Account contributions live here. For 2026, the HSA contribution limits are $4,400 for self-only coverage and $8,750 for family coverage, with an additional $1,000 catch-up for individuals age 55 or older.³

Direct cash disability payments are treated differently. Under a private employer-sponsored plan (not workers’ compensation), cash disability payments are FICA wages for the first six calendar months after the employee last worked, then excluded after that. Workers’ compensation payments are excluded from FICA from day one.

Group-term life insurance has its own line. Employer-provided coverage up to $50,000 is excluded from both income and FICA. The cost of coverage above $50,000, calculated using the IRS uniform premium tables, is a FICA wage.⁴

Business Expense Reimbursements

Reimbursements paid under an accountable plan are not FICA wages. An accountable plan requires substantiation with receipts, a business connection for the expense, and return of any excess reimbursement within a reasonable time. If the arrangement misses any of those three requirements, the IRS treats it as a non-accountable plan, and every dollar paid under it is a FICA wage reported in Boxes 1, 3, and 5 of Form W-2.⁵

Fringe Benefits

Certain fringe benefits excludable from gross income elsewhere in the tax code are also excluded from FICA wages. The ones that come up most often in practice:

Qualified transportation. Employer-provided transit passes, commuter van transportation, and qualified parking are excluded up to $340 per month per category for 2026.³
Working condition fringes. Property or services that would be deductible as a business expense if the employee had paid for them, such as job-related training, professional subscriptions, or a company vehicle used for business.⁶
De minimis fringes. Benefits so small that accounting for them would be impractical: occasional personal use of the office copier, a holiday turkey, break-room coffee. The benefit must be both infrequent and nominal.

Dependent Care Assistance

Amounts paid or incurred under a qualified dependent care assistance program are excluded from FICA wages up to $7,500 for 2026 for most filers, or $3,750 for a married individual filing separately.³ Amounts above the cap are FICA wages.⁷

Nonqualified Deferred Compensation: A Different Timing Rule

Amounts deferred under a nonqualified deferred compensation plan aren’t taxed for FICA on the usual pay-period timing. FICA applies at the later of when the employee performs the services creating the right to the compensation, or when that right is no longer subject to a substantial risk of forfeiture (essentially, when it vests).¹ Once FICA has been paid at that earlier point, the actual distribution years later isn’t taxed again for FICA.⁸

Front-loading FICA this way can benefit employees with rising compensation, because the deferred amount may be taxed before it pushes wages over the Social Security wage base, rather than years later when a lump-sum distribution might be much larger.

Tips

Cash tips of $20 or more received by an employee in a calendar month from a single employer are FICA wages. The employee must report those tips in writing to the employer by the tenth of the following month.⁹ The employer then owes its share of FICA on the reported tips and withholds the employee’s share from regular (non-tip) wages or from funds the employee provides.

When non-tip wages aren’t enough to cover the employee’s share, the employer reports the uncollected Social Security tax using Code A in Box 12 of Form W-2, and the uncollected Medicare tax using Code B.¹⁰ The employee picks up that amount on the individual return.

Employers in food service, barbering, hair care, nail care, and spa services can claim a credit under Section 45B for the employer-share Social Security tax paid on tips exceeding the amount needed to bring an employee’s wages up to the federal minimum wage.¹¹

When the Worker or the Work Changes the Answer

Before any payment can be a FICA wage, the person receiving it has to be an employee, and even then, certain categories of employment have their own rules.

Employee Classification

The primary test is the common-law standard. The IRS looks at behavioral control, financial control, and the nature of the relationship, weighing the overall picture rather than any single factor.¹² Section 3121(d) also designates four groups as statutory employees regardless of that analysis: certain agent-drivers and commission-drivers, full-time life insurance salespeople, home workers on materials supplied and returned, and full-time traveling or city salespeople soliciting orders for resale merchandise or business supplies.¹³ Misclassifying an employee as an independent contractor is one of the most expensive FICA mistakes an employer can make.

Agricultural Labor

Farm workers are subject to FICA only if the employer pays an individual $150 or more in cash wages during the year, or the employer’s total agricultural-labor expenditures reach $2,500 or more during the year.¹⁴ If either threshold is met, FICA applies to all cash wages. Non-cash compensation for agricultural labor is always excluded, regardless of amount.¹ Foreign agricultural workers lawfully admitted on a temporary basis, such as H-2A visa holders, are excluded from FICA employment entirely.

Household Employees

For 2026, if a household employer pays a single employee $3,000 or more in cash wages during the year, all cash wages paid to that employee are FICA wages.¹⁵ Below that threshold, no FICA tax is owed. Non-cash wages such as food or lodging are excluded regardless of amount.

Family Employees

Wages paid by a parent to a child under age 18 are exempt from FICA when the business is a sole proprietorship or a partnership in which every partner is a parent of the child. For domestic work in the parent’s private home, the exemption extends until the child turns 21.¹⁶ The exemption does not apply when the employer is a corporation or a partnership that includes non-parent partners.

Students

Services performed by a student enrolled and regularly attending classes at a school, college, or university, and working for that same institution, are generally excluded from FICA. The exemption applies only where the educational aspect of the relationship predominates. It doesn’t cover students working for an outside contractor that happens to operate on campus, and medical residents and interns employed by a hospital are typically treated as regular employees subject to FICA.

Government Employees

Federal employees hired after 1983 are generally covered by FICA. Those hired before 1984 who remain in certain legacy retirement systems may be exempt from Social Security but still pay Medicare. State and local government employment is excluded from FICA by default, with two significant exceptions. States can voluntarily enter Section 218 agreements with the Social Security Administration to provide FICA coverage; these agreements are irrevocable.¹⁷ And state or local employees who lack both a Section 218 agreement and membership in a qualifying public retirement system are subject to mandatory FICA coverage.

Religious Exemptions

Members of recognized religious groups that have existed continuously since December 31, 1950, and that are conscientiously opposed to accepting insurance benefits, can apply for exemption from FICA using Form 4029.¹⁸ The applicant waives all rights to Social Security and Medicare benefits, and the religious group must provide a reasonable level of living for its dependent members.

International Assignments

Services performed outside the United States by a U.S. citizen or resident are generally not FICA employment unless the worker is employed by an American employer, defined as a U.S. individual, partnership, trust, or corporation.¹ For workers sent to countries with totalization agreements, the agreement assigns coverage to one country to prevent double taxation. An employee temporarily transferred abroad for five years or fewer generally continues paying into the U.S. system and is exempt from the host country’s social security taxes; longer assignments typically shift to the host country’s system.¹⁹ The U.S. currently has these agreements with more than 30 countries.

Rates and the 2026 Wage Base

FICA has two components, each paid equally by employer and employee:

Social Security (OASDI): 6.2% from each party, for a combined 12.4%.²⁰
Medicare (HI): 1.45% from each party, for a combined 2.9%.²¹

The total FICA rate is 15.3% on applicable wages. The Social Security portion applies only up to the annual wage base, which for 2026 is $184,500.²² Once an employee’s FICA wages exceed that amount in a calendar year, no further Social Security tax is owed by either party on the excess. The Medicare tax has no wage base limit.

Additional Medicare Tax

High earners face an additional 0.9% Medicare surtax on FICA wages above thresholds that vary by filing status: $200,000 for single or head of household, $250,000 for married filing jointly, and $125,000 for married filing separately.²³

Employers must begin withholding the additional 0.9% once an employee’s wages pass $200,000 for the calendar year, regardless of the employee’s actual filing status. There is no employer match on this surtax. An employee whose wages exceed $200,000 effectively pays 2.35% in Medicare tax on wages above that threshold (1.45% plus 0.9%), while the employer’s rate stays at 1.45%.

Fixing FICA Errors, and What Happens If You Don’t

Employers correct previously reported FICA wages using Form 941-X.²⁴ For underreported wages, filing and paying by the due date of the return for the quarter in which the error was discovered generally avoids interest and penalties. For overreported wages, the employer can apply the credit to the current period’s return or file a claim for refund. The general deadline for either correction is three years from the date the original Form 941 was filed, or two years from the date the tax was paid, whichever is later.

Late FICA deposits trigger tiered penalties based on how many calendar days overdue the deposit is:²⁵

1 to 5 days late: 2% of the unpaid deposit
6 to 15 days late: 5%
More than 15 days late: 10%
More than 10 days after the first IRS notice, or upon receiving a demand for immediate payment: 15%

These tiers don’t stack. A deposit 20 days late triggers the 10% penalty, not 2% plus 5% plus 10%.

The employee’s share of FICA is a “trust fund” tax, held by the employer for the government. When a business fails to pay it over, the IRS can assess the Trust Fund Recovery Penalty against any individual who was responsible for collecting and paying the tax and who willfully failed to do so.²⁶ The penalty equals 100% of the unpaid trust fund portion. “Responsible persons” commonly include officers, directors, and anyone with authority over the company’s financial decisions. This is personal liability, and it is one of the few IRS tools that routinely pierces corporate protections.

1
Office of the Law Revision Counsel. 26 USC 3121 – Definitions
2
eCFR. 26 CFR 31.3121(a)(2)-1 – Payments on Account of Sickness or Accident Disability, Medical or Hospitalization Expenses, or Death
3
Internal Revenue Service. 2026 Publication 15-B, Employers Tax Guide to Fringe Benefits
4
Office of the Law Revision Counsel. 26 USC 79 – Group-Term Life Insurance Purchased for Employees
5
Internal Revenue Service. 2026 General Instructions for Forms W-2 and W-3
6
Office of the Law Revision Counsel. 26 USC 132 – Certain Fringe Benefits
7
Office of the Law Revision Counsel. 26 USC 129 – Dependent Care Assistance Programs
8
eCFR. 26 CFR 31.3121(v)(2)-1 – Treatment of Amounts Deferred Under Certain Nonqualified Deferred Compensation Plans
9
Internal Revenue Service. Topic No. 761, Tips – Withholding and Reporting
10
Internal Revenue Service. 2026 General Instructions for Forms W-2 and W-3 – Section: Box 12 Codes
11
Office of the Law Revision Counsel. 26 USC 45B – Credit for Portion of Employer Social Security Taxes Paid With Respect to Employee Cash Tips
12
Internal Revenue Service. Employee (Common-Law Employee)
13
eCFR. 26 CFR 31.3121(d)-1 – Who Are Employees
14
Internal Revenue Service. Publication 15 (2026), Circular E, Employers Tax Guide
15
Internal Revenue Service. Publication 926 (2026), Household Employers Tax Guide
16
Internal Revenue Service. Family Employees
17
Social Security Administration. Section 218 Agreements
18
Internal Revenue Service. Form 4029, Application for Exemption From Social Security and Medicare Taxes and Waiver of Benefits
19
Social Security Administration. Totalization Agreements
20
Internal Revenue Service. Topic No. 751, Social Security and Medicare Withholding Rates
21
Social Security Administration. Social Security and Medicare Tax Rates
22
Social Security Administration. Contribution and Benefit Base
23
Internal Revenue Service. Questions and Answers for the Additional Medicare Tax
24
Internal Revenue Service. Instructions for Form 941-X
25
Internal Revenue Service. Failure to Deposit Penalty
26
Office of the Law Revision Counsel. 26 USC 6672 – Failure to Collect and Pay Over Tax, or Attempt to Evade or Defeat Tax