What Is the Section 125 Tax Code and How Does It Work?

A Section 125 cafeteria plan is an employer-sponsored benefits arrangement that lets you pay for certain benefits with pre-tax dollars, lowering your federal income tax and your Social Security and Medicare taxes on every dollar you redirect. Named after Section 125 of the Internal Revenue Code, it gives you a choice between taking your full salary in cash or routing part of it into qualified benefits like health insurance premiums, flexible spending accounts, and dependent care assistance. Without this structure, the IRS would treat any benefit you could have taken as cash as taxable income under the constructive receipt doctrine. The cafeteria plan creates a legal exception, so the money you redirect never counts as wages for federal income tax, Social Security, or Medicare purposes.¹

How the Tax Savings Work

When you elect to redirect salary into a qualified benefit, that money is excluded from federal income tax, the 6.2% Social Security tax, and the 1.45% Medicare tax. Depending on your federal bracket and state rules, participants typically save between 20% and 40% on every dollar run through the plan. If you are in the 22% federal bracket and put $3,400 into a health flexible spending account, you avoid roughly $850 in federal income tax and another $260 in FICA on that amount alone.

Your employer saves too. Salary reductions under a cafeteria plan are excluded from wages for FICA and FUTA purposes, so the employer avoids its matching 6.2% Social Security tax, 1.45% Medicare tax, and FUTA tax on every dollar you redirect.² That shared savings is part of why employers offer these plans at all.

A handful of states do not fully conform to the federal Section 125 treatment. In those states, you may still owe state income tax on some or all of your salary reductions even though the money is exempt federally. Check your state’s rules before assuming every dollar is completely tax-free.

What You Can Pay For Through the Plan

To be offered through a cafeteria plan, a benefit must be specifically excludable from your gross income under another section of the Internal Revenue Code. The most common qualified benefits are:

Medical, dental, and vision insurance premiums paid by the employee.
Health Flexible Spending Accounts, which reimburse out-of-pocket medical expenses.
Dependent Care Assistance Programs for eligible childcare or adult dependent care costs.
Group-term life insurance, fully excludable on coverage up to $50,000. The cost of coverage above $50,000 is taxable based on an IRS premium table.³
Adoption assistance for qualified adoption expenses.
Employer contributions to an employee’s Health Savings Account, when paired with a high-deductible health plan.

Several benefits are specifically barred. Long-term care insurance cannot run through a cafeteria plan. Scholarships, educational assistance, and most fringe benefits under Section 132 are excluded. Marketplace health plans purchased through the ACA exchanges generally cannot be included either, with a narrow exception for certain small employers.¹

Common Plan Structures

Most employers choose between two setups. A Premium Only Plan is the simplest version: it does nothing except let you pay your share of health, dental, and vision premiums pre-tax. No FSAs, no dependent care accounts. A Full Cafeteria Plan bundles premium payments with one or more additional benefits like Health FSAs, Dependent Care Assistance Programs, adoption assistance, and group-term life insurance. If you only see “pre-tax premium deduction” on your paystub and no FSA option, your employer is probably running a POP.

Making Your Election and Changing It Mid-Year

Before each plan year, you choose how much salary to redirect and which benefits to fund. The election must be made in writing and is generally locked in for the entire plan year. That irrevocability is what makes the tax exclusion work: because you cannot change your mind and take the money as cash, the IRS agrees the money was never constructively received.¹

You can only change your election mid-year after a qualifying life event, and only if your plan document specifically allows the change. The IRS regulations recognize several categories:⁴

Change in marital status: marriage, divorce, legal separation, annulment, or death of a spouse.
Change in number of dependents: birth, adoption, placement for adoption, or death of a dependent.
Change in employment status for you, a spouse, or a dependent, where the change affects health plan eligibility.
A child aging out of coverage or gaining eligibility under another plan.
Events that trigger HIPAA special enrollment, like losing other coverage or gaining a new dependent.

The change you request has to be consistent with the event. A divorce can justify dropping a former spouse from your health plan, but it does not justify adding a vision benefit you previously declined. Most plans give you 30 days from the event to request the change, though the specific window is set by your employer’s plan document rather than the IRS.

Financial hardship is not a qualifying event. However tight your budget gets, you cannot reduce or stop your FSA contributions mid-year just because you need the cash. This is where the irrevocability rule bites hardest, and it is the most common source of frustration participants have with these plans.

Flexible Spending Accounts Inside the Plan

FSAs are the component that needs the most active management from you. There are two main types, each with its own limits and rules.

Health FSA

A Health FSA reimburses out-of-pocket medical, dental, and vision expenses not covered by insurance. For plan year 2026, the maximum employee contribution is $3,400.⁵ The IRS adjusts this limit annually for inflation.

Health FSAs follow the uniform coverage rule: your full annual election is available for reimbursement from the first day of the plan year, no matter how much has been deducted from your paychecks so far. If you elect $3,400 and have a $3,000 medical expense in January after contributing only $280, the plan must reimburse the full $3,000. Your employer absorbs the risk if you leave before your contributions catch up.

Dependent Care FSA

A Dependent Care Assistance Program covers care for a qualifying dependent that lets you work. Common expenses include daycare, preschool, after-school programs, and elder care. The statutory annual limit is $7,500 per household, or $3,750 if you are married filing separately.⁶ Unlike Health FSAs, Dependent Care FSAs are not subject to uniform coverage. You can only be reimbursed up to what you have actually contributed so far.

Use-It-or-Lose-It

Both FSAs are subject to the use-it-or-lose-it rule: anything left in the account at the end of the plan year is forfeited to your employer. The IRS allows employers to soften this with one of two relief options, but not both:

Grace period: an extra two and a half months after the plan year ends to incur eligible expenses. For a calendar-year plan, that means expenses through March 15 still count. This option applies to both Health and Dependent Care FSAs.⁷
Carryover: Health FSAs only. For plan years beginning in 2026, up to $680 of unused funds can roll into the next plan year. Employers can set a lower cap.⁵

Overestimating in October and forfeiting hundreds of dollars in December is the single most common FSA mistake. Base your election on recurring, predictable costs like monthly prescriptions, regular copays, or scheduled dental work rather than speculative expenses.

If You Also Want an HSA

If your employer offers a high-deductible health plan with an HSA, a general-purpose Health FSA will disqualify you from making HSA contributions. The IRS treats a traditional Health FSA as other health coverage because it reimburses medical expenses below the HDHP deductible.⁸

The workaround is a limited-purpose FSA, which only reimburses dental and vision expenses. Because the IRS disregards dental and vision coverage when determining HSA eligibility, a limited-purpose FSA lets you keep contributing to your HSA while still getting a pre-tax benefit on eye exams and dental work.⁹ The 2026 limit is the same $3,400, and the $680 carryover applies as well. A Dependent Care FSA does not affect HSA eligibility, so you can run both without conflict.

What Happens If You Leave Your Job

Leaving mid-year raises immediate questions about your FSA balance. For a Health FSA, you can only submit claims for expenses incurred before your termination date, and only if your contributions are current. Any remaining balance after your final claims is forfeited. If you already spent more than you contributed, which is possible under the uniform coverage rule, your employer cannot come after you for the difference.

Health FSAs are technically subject to COBRA continuation coverage. If you have a positive balance at termination, your employer must offer you the option to continue the FSA through the end of the plan year by paying the full contribution amount yourself, including what the employer previously covered. In practice, COBRA on an FSA rarely makes financial sense unless you have significant known medical expenses coming, because you are paying the full cost with after-tax dollars and losing the primary advantage of the arrangement.

Dependent Care FSAs are not subject to COBRA. You can still submit claims for eligible expenses incurred during the plan year up to the amount you had already contributed before you left.

1
Office of the Law Revision Counsel. 26 USC 125 Cafeteria Plans
2
Internal Revenue Service. FAQs for Government Entities Regarding Cafeteria Plans
3
Internal Revenue Service. Group-Term Life Insurance
4
eCFR. 26 CFR 1.125-4 Permitted Election Changes
5
FSAFEDS. New 2026 Maximum Limit Updates
6
Office of the Law Revision Counsel. 26 USC 129 Dependent Care Assistance Programs
7
Internal Revenue Service. Eligible Employees Can Use Tax-Free Dollars for Medical Expenses
8
Office of the Law Revision Counsel. 26 USC 223 Health Savings Accounts
9
Internal Revenue Service. Publication 969 Health Savings Accounts and Other Tax-Favored Health Plans