A pre-tax deduction, or deducción antes de impuestos in Spanish, is money your employer subtracts from your paycheck before calculating the taxes you owe. Because that amount never counts as taxable income, your tax bill shrinks on every paycheck. These deductions pay for benefits like retirement savings, health insurance, and medical spending accounts, and they show up as line items on your pay stub (talón de pago) between your gross pay and the tax withholding.
Paystub Terms in English and Spanish
Most confusion starts with the pay stub itself. The IRS publishes an official English-Spanish tax glossary that translates common payroll terms.1Internal Revenue Service. Publication 850 (EN-SP) – English-Spanish Glossary of Tax Words and Phrases These are the words you will see most often:
- Gross Pay / Ingreso Bruto: your total earnings before any deductions or taxes.
- Deductions / Deducciones: amounts subtracted from your gross pay. Pre-tax deductions come out before the tax calculation; after-tax deductions come out after.
- Withholding / Retención: the federal and state income tax your employer holds back and sends to the government for you.
- Taxable Income / Ingreso Tributable: the portion of your gross pay left after pre-tax deductions. This is the number the government actually taxes.
- Net Pay / Ingreso Neto: your take-home pay after everything has been subtracted.
- Health Insurance Premium / Prima del Seguro Médico: what you pay each pay period for medical, dental, or vision coverage.
- Retirement Contribution / Aportación para Jubilación: money directed into a 401(k) or similar retirement account.
When a line item on your stub is labeled “pre-tax,” that amount was taken out of your gross pay before taxes were calculated. Your taxable income drops, and so does your tax.
How Pre-Tax Deductions Lower Your Taxes
Federal income tax rates range from 10% to 37%, applied in layers called brackets.2Internal Revenue Service. Federal Income Tax Rates and Brackets Every dollar classified as a pre-tax deduction never enters that bracket calculation. If you earn $1,000 in a pay period and contribute $100 to a pre-tax benefit, the IRS only sees $900 of taxable income for that period.
Here is the detail many workers miss: not every pre-tax deduction reduces every kind of tax. Some lower your federal income tax but still count toward Social Security (6.2%) and Medicare (1.45%) taxes.3Social Security Administration. FICA and SECA Tax Rates Others reduce all three.
Deductions That Reduce Only Income Tax
Traditional 401(k) contributions are the classic example. The money you defer escapes federal income tax withholding, but your employer still calculates Social Security and Medicare taxes on the full amount.4Internal Revenue Service. Are Retirement Plan Contributions Subject to Withholding for FICA, Medicare, or Federal Income Tax So increasing your 401(k) percentage will not change your FICA withholding.
Deductions That Reduce Income Tax and FICA
Benefits offered through a Section 125 cafeteria plan, including health insurance premiums, FSA contributions, and similar qualified benefits, reduce your wages for income tax, Social Security, and Medicare at the same time.5Internal Revenue Service. FAQs for Government Entities Regarding Cafeteria Plans The federal tax code specifically excludes these salary reductions from FICA wages.6Office of the Law Revision Counsel. 26 USC 3121 – Definitions That double savings makes cafeteria plan deductions especially valuable dollar for dollar compared with retirement deferrals.
Common Types of Pre-Tax Deductions
Retirement Contributions (401(k), 403(b), 457)
The 401(k) is the most common employer-sponsored retirement plan. For 2026, you can defer up to $24,500 of your pay into a traditional 401(k) before income taxes apply. If you are 50 or older, you can add $8,000 in catch-up contributions. Workers aged 60 through 63 get a higher catch-up limit of $11,250 under the SECURE 2.0 Act.7Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500 The same limits apply to 403(b) plans (common in schools and hospitals) and most government 457 plans.
The money grows without being taxed until you withdraw it, usually after age 59½. Pulling it out earlier generally triggers income tax plus a 10% early withdrawal penalty.
Health Insurance Premiums
If your employer offers coverage through a Section 125 cafeteria plan, the premiums you pay for medical, dental, and vision insurance come out before all taxes, including FICA.5Internal Revenue Service. FAQs for Government Entities Regarding Cafeteria Plans Most workers do not notice it is happening because payroll handles it automatically, but it is one of the most valuable tax breaks available to employees with employer-sponsored coverage.
Flexible Spending Accounts (FSA)
A health care FSA lets you set aside pre-tax dollars for medical expenses your insurance does not cover, like copays, prescription eyeglasses, and certain over-the-counter medications. For 2026, the maximum contribution is $3,400. A separate dependent care FSA covers childcare and elder care while you work, with a standard annual limit of $5,000 per household ($2,500 if married filing separately).
FSAs carry a use-it-or-lose-it rule. Any money left in the account at the end of the plan year goes back to your employer. Some employers soften this by offering one of two options, never both: a grace period of up to two and a half extra months to spend remaining funds, or a carryover of up to $680 of unused health FSA funds into the next year. Before electing a large FSA contribution, find out which option your employer provides. One wrinkle: carrying over unused health FSA funds can make you ineligible to contribute to an HSA that year, even if you did not make a new FSA election.
Health Savings Accounts (HSA)
HSAs are available only if you are enrolled in a high-deductible health plan. For 2026, you can contribute up to $4,400 for individual coverage or $8,750 for family coverage. Contributions through payroll reduce both income tax and FICA. Unlike an FSA, unused HSA funds roll over indefinitely, and the account belongs to you permanently, even if you change jobs.
HSA money spent on qualified medical expenses comes out tax-free.8Internal Revenue Service. Publication 969 – Health Savings Accounts and Other Tax-Favored Health Plans Use it for non-medical expenses before age 65 and you will owe income tax plus a 20% penalty. After 65 the penalty disappears, but you still pay income tax on non-medical withdrawals.
Commuter and Parking Benefits
Qualified transportation fringe benefits let you pay for transit passes, vanpooling, or qualified parking with pre-tax dollars. For 2026, the monthly exclusion is $340 for both transit and parking.9Internal Revenue Service. Employer’s Tax Guide to Fringe Benefits Not every employer offers this, but it is common in cities with public transit systems.
Pre-Tax vs. Post-Tax (Roth) Deductions
Some employers offer both traditional pre-tax and Roth options for retirement contributions. The difference is when you pay taxes. With a pre-tax 401(k), your taxable income drops now, but you will pay income tax on every dollar you withdraw in retirement. With a Roth 401(k), you pay taxes on the contribution today, and qualified withdrawals in retirement come out completely tax-free, including the investment gains.
On your pay stub, a Roth contribution shows as an after-tax deduction. It does not lower your current taxable income, so your paycheck will be smaller today than if the same dollar amount went into a traditional pre-tax account. Neither option is universally better; it depends on your current income, your expected retirement income, and how long the money has to grow.
When You Can Enroll or Change Your Deductions
You cannot change most pre-tax deductions whenever you want. Health insurance, FSAs, and similar cafeteria plan benefits lock in during your employer’s annual open enrollment period, which typically runs for a few weeks in the fall before the new plan year starts. Miss the window and you are generally stuck with your current elections for the year.
The exception is a qualifying life event, which usually opens a special 30-day enrollment window. Events that trigger it include:10HealthCare.gov. Qualifying Life Event (QLE)
- Loss of coverage, such as losing job-based insurance, aging off a parent’s plan at 26, or losing Medicaid or CHIP.
- Household changes, including marriage, divorce, birth or adoption of a child, or a death in the family.
- Moving to a different ZIP code or county where different plans are available.
- Other events like income changes that affect subsidy eligibility, gaining citizenship, or leaving incarceration.
Any election change must correspond to the life event. A new baby is not a reason to drop dental coverage, for example. The change has to be consistent with the qualifying event, and the cafeteria plan itself must permit mid-year changes; it is not required to.11eCFR. 26 CFR 1.125-4 – Permitted Election Changes Retirement plan contributions like 401(k) deferrals are more flexible and can typically be adjusted any time, though your employer’s plan document may impose its own waiting periods.
What Happens When You Leave the Job
Not all pre-tax accounts follow you out the door. The rules depend on the type of account.
Your HSA is yours permanently. The account belongs to you, not your employer, and you keep the full balance whether you quit, get laid off, or retire.8Internal Revenue Service. Publication 969 – Health Savings Accounts and Other Tax-Favored Health Plans
Your 401(k) balance also belongs to you. You can leave it in the former employer’s plan, roll it into a new employer’s plan, or transfer it to an IRA. Cashing it out before 59½ triggers income tax and the 10% early withdrawal penalty.
FSAs are the harshest. Unused health FSA funds generally revert to your employer. If you have contributed more than you have spent, you may be eligible for COBRA continuation on the FSA, which lets you keep submitting claims for the rest of the plan year, though you would pay the contributions on an after-tax basis. If you have already spent more than you have contributed for the year, the employer absorbs the loss and COBRA will not apply. Plan to spend down your FSA balance before leaving a job whenever possible.
State Taxes
Federal pre-tax treatment does not guarantee your state agrees. Most states follow the federal rules and exclude 401(k) deferrals and Section 125 benefits from state income tax, but a handful treat certain contributions differently. A few states, for example, do not recognize HSA contributions as tax-exempt for state purposes, meaning you would owe state income tax on those dollars even though the federal government does not tax them. States with no income tax make this a non-issue. Check your state’s rules before assuming the federal treatment applies across the board.