Pretax money is the portion of your paycheck that your employer routes into eligible benefits before calculating federal income tax withholding. That routing shrinks the wages the IRS sees, so you owe less tax on the same gross pay. The savings show up twice: less tax withheld from every paycheck during the year, and a smaller taxable-wage figure in Box 1 of your W-2 at year-end.
Because the money never counts as taxable income in the first place, you don’t claim a separate deduction for it when you file. Benefits offered through an employer’s cafeteria plan under Section 125 of the Internal Revenue Code are technically an income exclusion rather than a deduction, but the effect on your tax bill is the same.1Office of the Law Revision Counsel. 26 USC 125 – Cafeteria Plans2Internal Revenue Service. FAQs for Government Entities Regarding Cafeteria Plans
Where Pretax Money Can Go
Most pretax dollars land in one of three places: retirement plans, health accounts, or commuter benefits. Each has its own IRS ceiling, and those ceilings usually adjust for inflation each year.
On the retirement side, the 401(k) is the standard vehicle at for-profit employers; nonprofits, schools, and some government agencies offer the 403(b). Both work the same way for tax purposes. Money leaves your paycheck before federal income tax is withheld, grows tax-deferred inside the account, and gets taxed as ordinary income when you eventually pull it out. For 2026, the employee contribution limit is $24,500. Workers 50 and older can add an $8,000 catch-up, for a total of $32,500. A SECURE 2.0 provision opens a higher catch-up window for workers aged 60 through 63, allowing $11,250 on top of the base for a combined $35,750.3Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500
Health accounts come in two flavors. A Health Savings Account (HSA) requires enrollment in a high-deductible health plan and has no spending deadline; unused balances roll over indefinitely. A healthcare Flexible Spending Account (FSA) is available with most employer health plans but generally must be spent within the plan year, with only a limited carryover or grace period if your employer allows one. For 2026, HSA limits are $4,400 for self-only coverage and $8,750 for family coverage, with an extra $1,000 catch-up available at 55 if you aren’t yet on Medicare.4Internal Revenue Service. Notice 2026-5 – Health Savings Accounts Under the One, Big, Beautiful Bill Act The 2026 healthcare FSA limit is $3,400.
Commuter benefits are the quietest of the three. If your employer offers a qualified transportation plan, you can direct pretax money to transit passes, vanpool costs, or qualified parking. The 2026 caps are $340 per month for transit and vanpool and a separate $340 per month for parking, worth as much as $8,160 a year if you use both.5Internal Revenue Service. Publication 15-B – Employer’s Tax Guide to Fringe Benefits (For Use in 2026)
How the Tax Cut Actually Works on Your Paycheck
Your employer subtracts pretax contributions from your gross pay before running the withholding calculation. The wage figure that gets taxed on that paycheck is smaller, so the withholding is smaller. At the end of the year, Box 1 of your W-2 reports that reduced number to the IRS as your taxable wages.
A quick example. Say you earn $65,000 and contribute $6,000 to a 401(k) plus $2,400 to an HSA over the year. Your W-2 Box 1 will show roughly $56,600 in taxable wages instead of $65,000. You still earned the full $65,000, but federal income tax only applies to $56,600. Depending on your bracket, the difference is worth anywhere from a few hundred to a few thousand dollars.
Which Taxes Pretax Money Doesn’t Escape
This is where the rules diverge, and it catches people out. Not every pretax deduction avoids every payroll tax.
Contributions to a 401(k) or 403(b) dodge federal income tax withholding but stay subject to Social Security and Medicare (FICA) taxes. Your employer still withholds 6.2% for Social Security and 1.45% for Medicare on those dollars.6Internal Revenue Service. 401(k) Plan Overview A full $24,500 401(k) contribution still generates roughly $1,873 in FICA on that amount.
Health insurance premiums and FSA contributions running through a Section 125 cafeteria plan get better treatment. Those amounts are generally excluded from FICA as well as income tax, an extra 7.65% saved compared with paying for the same items with after-tax money.7Internal Revenue Service. Employee Benefits
State income tax is another wrinkle. Most states follow the federal treatment and exclude 401(k) and 403(b) contributions from state taxable income, but a handful tax those contributions at the state level anyway. If your pay stub shows state tax being calculated on a higher wage than your W-2 Box 1, that’s why.
The Strings Attached
The tax break is real, but the money isn’t freely yours to grab back. Each account type has its own rules on getting the money out, and breaking those rules costs more than the tax you saved.
For 401(k) and 403(b) plans, withdrawing before age 59½ generally triggers regular income tax on the full amount plus a 10% early distribution penalty. Some exceptions apply. If you leave your employer during or after the year you turn 55, for instance, you can withdraw from that employer’s plan without the 10% hit. Hardship withdrawals and certain other circumstances may also qualify, though the income tax still applies.8Internal Revenue Service. Retirement Topics – Exceptions to Tax on Early Distributions
HSAs are stricter about non-medical use. Pull money out for anything other than qualified medical expenses before age 65 and you’ll owe income tax plus a 20% additional tax. After 65, the 20% penalty falls away and non-medical withdrawals are simply taxed as ordinary income, so the HSA starts behaving like a traditional retirement account.9Internal Revenue Service. Publication 969 (2025) – Health Savings Accounts and Other Tax-Favored Health Plans
FSAs don’t have an early-withdrawal penalty because the money is meant to be spent within the plan year. The risk is the opposite: unspent balances are forfeited, minus any carryover your employer permits. That’s the reason conservative FSA elections tend to work out better than optimistic ones.
One more trap sits on the retirement side. Contribute more than the annual 401(k) or 403(b) limit and you have an excess deferral. Contact the plan administrator and request a withdrawal of the excess plus its earnings by April 15 of the following year, and the excess is taxed in the year you contributed it while the earnings are taxed in the year they come out. No early withdrawal penalty applies to a timely correction. Miss the April 15 deadline and the excess gets taxed twice, once in the contribution year and again when it eventually leaves the plan, potentially with the 10% early withdrawal penalty and mandatory 20% withholding on top.10Internal Revenue Service. 401(k) Plan Fix-It Guide – Elective Deferrals Weren’t Limited to the Amounts Under IRC Section 402(g) The people this hits most often are those who change jobs mid-year and contribute to two separate plans without adding up the totals.