Pre-Tax Deduction: What It Means for Employers

What it means in practice

Every paycheck starts with gross pay. A payroll deduction is pre-tax when federal tax law lets the amount be left out of wages for one or more taxes, so those taxes are figured on what remains. The tax savings come from the plan type, not from what the employer calls the deduction on a pay stub. The same dollars can be pre-tax for income tax but still taxed for FICA, so the useful question is always "pre-tax for which tax?"

Section 125 cafeteria plans. Under 26 U.S.C. 125, a cafeteria plan is a written plan under which all participants are employees and may choose among two or more benefits consisting of cash and qualified benefits; choosing a qualified benefit does not by itself make it taxable. IRS Publication 15-B (2026) says a cafeteria plan "provides participants an opportunity to receive qualified benefits on a pre-tax basis." Qualified benefits it lists include accident and health benefits, adoption assistance, dependent care assistance, group-term life insurance coverage and HSAs. A cafeteria plan cannot include transportation (commuting) benefits, educational assistance, meals, de minimis benefits or most other fringe benefits, and generally cannot offer benefits that defer pay, except that it can include a qualified 401(k) plan (Pub 15-B; 26 U.S.C. 125(d)(2)).

How cafeteria plan deductions are taxed. Publication 15 (2026) says that if an employee chooses cash or another taxable benefit, the amount is subject to all employment taxes; if the employee chooses a nontaxable benefit, "the treatment is the same as if the benefit was provided outside the plan." The Social Security and FUTA wage definitions exclude payments under a cafeteria plan when the payment would not be wages without the plan (26 U.S.C. 3121(a)(5)(G) and 3306(b)(5)(G)). Table 2-1 of Publication 15-B shows accident and health benefits as exempt from income tax withholding, Social Security, Medicare and FUTA, and dependent care assistance as exempt up to $7,500 ($3,750 for a married employee filing separately).

Health FSAs. A health flexible spending account runs through a cafeteria plan. For plan years beginning in 2026, a cafeteria plan may not allow an employee to request health FSA salary reduction contributions above $3,400, and a plan that does not limit contributions to the dollar limit "isn't a cafeteria plan," making all benefits under it includible in gross income (Pub 15-B). The $3,400 limit does not include up to $680 carried over from a prior year (2026 W-2 Instructions).

HSAs. For a health savings account, the route matters. Publication 15 says employee HSA contributions through an ordinary payroll deduction plan are wages subject to Social Security, Medicare, FUTA and income tax withholding, but HSA contributions under a salary reduction arrangement in a section 125 cafeteria plan "aren't wages and aren't subject to employment taxes or withholding." For 2026, Publication 15-B sets the limit at $4,400 for self-only HDHP coverage and $8,750 for family coverage, plus $1,000 for a qualified individual age 55 or older. Partners and 2% shareholders of an S corporation are not eligible for pre-tax HSA salary reductions.

401(k) and 403(b) elective deferrals. Publication 15's table of special rules shows elective deferrals to a 401(k) plan as generally exempt from income tax withholding (subject to the section 402(g) limit) but taxable for Social Security, Medicare and FUTA. Salary reduction contributions to 403(b) annuities are treated the same way, as are employee salary reduction contributions to a SIMPLE retirement account or a section 457(b) plan. The statute says the same thing: 26 U.S.C. 3121(v)(1)(A) keeps 401(k) contributions excluded from gross income inside "wages" for FICA. The IRS sets the 2026 elective deferral limit for traditional and safe harbor 401(k) plans at $24,500, with catch-up contributions of up to $8,000 at age 50 or older, or $11,250 for employees aged 60 to 63.

Roth deferrals are not pre-tax. The IRS says a designated Roth contribution is an elective deferral the employee "irrevocably designates" as an after-tax contribution. The employer includes it in gross income when the employee would otherwise have received the cash, and "it is subject to all applicable wage-withholding requirements." Starting in 2026, participants in plans with Roth features must make catch-up contributions on a Roth basis if their prior-year wages from the plan sponsor exceeded $150,000 (IRS catch-up contributions page).

Commuter benefits. Transit and parking benefits sit outside the cafeteria plan, under the qualified transportation fringe rules of section 132(f). Publication 15-B says a compensation reduction agreement "is a way to provide qualified transportation benefits on a pre-tax basis" by letting employees choose between cash and the benefit, and the monthly reduction cannot exceed the monthly limits. For 2026, the exclusion is $340 a month for combined commuter highway vehicle transportation and transit passes and $340 a month for qualified parking. Qualified transportation benefits are exempt from income tax withholding, Social Security, Medicare and FUTA up to those limits, and value over the limit, minus anything the employee paid, goes into wages. Bicycle commuting reimbursements no longer qualify: P.L. 119-21 permanently eliminated that exclusion for tax years beginning after 2025.

Who can take part. For cafeteria plans, Publication 15-B treats a 2% shareholder of an S corporation like a partner, not an employee. A self-employed individual is not an employee for qualified transportation benefits. If a cafeteria plan favors highly compensated or key employees, the taxable benefits they could have chosen go into their wages. For 2026, a key employee is generally an officer paid more than $235,000, a 5% owner, or a 1% owner paid more than $150,000.

How it works in payroll, step by step. (1) Identify the plan behind each deduction: cafeteria plan, retirement plan, transportation compensation reduction agreement or none. (2) Subtract each deduction only from the wage bases it is excluded from: income tax, Social Security and Medicare, or FUTA. (3) Apply the 2026 limits each pay period and year to date. (4) Withhold and pay taxes on the reduced bases; Social Security is 6.2% each for employer and employee up to the 2026 wage base of $184,500, Medicare is 1.45% each, and FUTA applies to the first $7,000 of wages (Pub 15, 2026). (5) Report the amounts correctly on Form W-2.

W-2 reporting. The 2026 General Instructions for Forms W-2 and W-3 say box 1 should not include elective deferrals such as employee contributions to a 401(k) or 403(b) plan, but box 3 must include deferrals reported in box 12 with codes D, E, F, G and S. Box 12 shows 401(k) deferrals with code D and 403(b) deferrals with code E. Designated Roth contributions are included in boxes 1 and 3 and shown with code AA (401(k)) or BB (403(b)). Employer HSA contributions, including amounts the employee elected through a cafeteria plan, use code W. Dependent care benefits go in box 10, including pre-tax contributions under a section 125 dependent care FSA. Code DD shows the cost of employer-sponsored health coverage, which "is not taxable." The instructions' own example has Alex (age 45) defer $26,500 in 2026, above the $24,500 limit: the employer reports D 26500.00 in box 12, and the excess is not reported in box 1. See our Form W-2 guide for the full form.

Worked example 1: net pay with and without pre-tax deductions. A Remindax illustration with assumed numbers: an employee earns $2,000 gross per biweekly pay period, pays $100 for health coverage and puts $150 into the 401(k) plan. Federal income tax withholding is shown at an assumed flat 12%; real withholding comes from IRS Publication 15-T and the employee's Form W-4. Scenario A, all after-tax (premium paid outside a cafeteria plan, Roth deferral): income tax wages $2,000, withholding $240.00; FICA wages $2,000, Social Security $124.00 and Medicare $29.00. Net pay is $2,000 - $240.00 - $153.00 - $100 - $150 = $1,357.00. Scenario B, pre-tax (premium through a section 125 plan, traditional 401(k)): income tax wages $1,750, withholding $210.00; FICA wages $1,900 because the 401(k) deferral stays in, Social Security $117.80 and Medicare $27.55. Net pay is $2,000 - $210.00 - $145.35 - $100 - $150 = $1,394.65, or $37.65 more. Of that, $30.00 is income tax on the $250 and $7.65 is FICA on the $100 premium only. The employer's matching FICA also falls by $7.65.

Worked example 2: commuter benefit over the limit. Assumed numbers: in a 2026 month an employee elects a $400 transit benefit through a compensation reduction agreement. The first $340 is excluded. Under Publication 15-B, the $60 over the limit, minus any amount the employee paid for the benefit, is included in wages.

Worked example 3: the IRS dependent care example. In Publication 15-B, Oak Co. provides a dependent care FSA through a cafeteria plan and occasional free on-site care. Emily had $7,000 deducted from her pay for the FSA and used on-site care worth $700. Her W-2 reports $7,700 in box 10, and boxes 1, 3 and 5 include $200, the amount over the $7,500 exclusion, with taxes withheld on it.

Where states differ. State income tax treatment can differ from the federal rules. Two examples from official state pages: the New Jersey Division of Taxation (Technical Bulletin TB-39(R), issued March 3, 2003) says New Jersey Gross Income Tax law does not adopt the federal treatment of section 125 cafeteria plans, so benefits provided through a salary reduction agreement, including FSAs and premium conversion options, are generally included in New Jersey wages and withholding. In its example, Sue reduces her salary by $2,400 for health coverage and her full salary stays subject to New Jersey tax. The same bulletin says New Jersey follows federal treatment for qualified 401(k) contributions. Pennsylvania's Personal Income Tax Guide says employee contributions to a qualified section 125 plan for hospitalization, sickness, disability or death coverage are exempt to the extent they are exempt federally, but employee contributions for dependent care and to a section 401 plan are not excludable, and 401(k) and 403(b) deferrals are listed as taxable employee contributions. Check your own state's tax agency before setting state withholding.

Minimum wage and other FLSA rules. The Fair Labor Standards Act looks at deductions differently from the tax code. Wages must be paid "finally and unconditionally or free and clear," and the wage requirements are not met where an employee kicks back part of the wage to the employer or another person for the employer's benefit (29 CFR 531.35). Sums the employee voluntarily directs the employer to pay to a third party for the employee's benefit count as wages paid, provided the employer derives no profit or benefit; insurance premiums paid to independent insurers are one of the listed examples (29 CFR 531.40). The employee's share of Social Security and other taxes can also be counted as wages paid (29 CFR 531.38). By contrast, DOL Fact Sheet #16 says deductions for items for the employer's benefit, such as required uniforms, may not cut into the minimum wage or overtime pay.

Recordkeeping. FLSA payroll records must show total additions to or deductions from wages each pay period and, in individual employee records, the dates, amounts and nature of the items that make up those totals (29 CFR 516.2(a)(10)).

Questions employers ask. Do pre-tax deductions lower Social Security wages? Cafeteria plan deductions generally do; 401(k) and 403(b) deferrals do not (Pub 15; Pub 15-B). Can commuter benefits go in the cafeteria plan? No; Publication 15-B lists transportation benefits as not allowed in a cafeteria plan and provides them through a separate compensation reduction agreement. What if an employee elects more than $3,400 to a health FSA by mistake? The W-2 Instructions say the plan stays a cafeteria plan if the error was a reasonable mistake and the excess is paid to the employee and reported as wages. Confirm specifics with a qualified tax professional.

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