After-tax deductions on your paycheck are the amounts your employer subtracts after federal, state, and payroll taxes have already been calculated on your gross wages. Because the tax has already been figured, these deductions don’t lower your taxable income for the year. They fall into two groups: things you signed up for, like Roth 401(k) contributions or supplemental insurance premiums, and things imposed on you, like wage garnishments, child support orders, and IRS levies.
Why the After-Tax Label Matters
Every deduction on your stub is either pre-tax or after-tax, and the timing decides whether it changes your tax bill. Pre-tax deductions come out before your employer calculates withholding, so they shrink the wages the IRS sees. Traditional 401(k) contributions, health insurance premiums run through a Section 125 cafeteria plan, HSA deposits, and FSA contributions all work this way. Earn $5,000 in a period and put $500 into a traditional 401(k), and your taxable wages for that period drop to $4,500.
After-tax deductions come out on the other side of the tax calculation. Your taxable income is the same whether you authorize them or not. The clearest example is a Roth 401(k) or Roth 403(b) contribution: you pay tax on the money now, and qualified withdrawals in retirement come out tax-free.1Internal Revenue Service. Retirement Topics – Designated Roth Account The practical trade-off is that pre-tax deductions save money today and create a tax bill later, while after-tax deductions cost more upfront and can save you money later.
What you have left after the mandatory withholdings, including federal income tax, FICA (6.2% Social Security up to the $184,500 wage base in 2026, plus 1.45% Medicare on every dollar),2Internal Revenue Service. Topic No. 751, Social Security and Medicare Withholding Rates3Social Security Administration. Contribution and Benefit Base and any state or local income tax, is your disposable earnings.4Office of the Law Revision Counsel. 15 USC 1672 – Definitions That figure is the starting point for every after-tax deduction on your stub.
Voluntary After-Tax Deductions You Signed Up For
Nothing in this group appears on your paycheck unless you authorized it, and you can generally cancel it by giving your employer or HR department written notice.
Roth Retirement Contributions
Roth 401(k) and Roth 403(b) contributions are the biggest voluntary after-tax line for most workers. You pay tax on the dollars going in, but qualified retirement withdrawals, including all the investment growth, come out tax-free.1Internal Revenue Service. Retirement Topics – Designated Roth Account For 2026, the basic elective deferral limit for 401(k) and 403(b) plans is $24,500. That cap applies to your combined traditional and Roth contributions, not to each separately. Workers age 50 and older can put in additional catch-up contributions above the limit.5Internal Revenue Service. Retirement Topics – Contributions
Supplemental Insurance Premiums
Your main employer-sponsored health insurance premium is usually pre-tax because it runs through a Section 125 plan. Supplemental coverage usually isn’t. Disability insurance, supplemental life insurance beyond a basic employer-provided policy, accident insurance, and critical illness plans typically come out post-tax. One upside: if you ever file a claim on a disability policy paid with after-tax dollars, the benefits you receive are generally not taxable income.
Union Dues
Union members commonly have their dues deducted automatically each pay period. These come out after taxes. Before 2018, dues were deductible on your federal return as an unreimbursed employee expense if you itemized. That deduction is currently suspended through 2025 under the Tax Cuts and Jobs Act, and its status for later years depends on whether Congress extends those provisions.
Workplace Giving and Other Post-Tax Items
Many employers run workplace giving programs that let you route a recurring donation from your paycheck to organizations like the United Way. Those deductions are after-tax. You may still be able to claim them as itemized charitable deductions on your return, but the payroll line itself doesn’t reduce your withheld wages. Other after-tax items in this category can include repayment of an employer loan, purchases through a company store, and parking fees not covered under a qualified transportation benefit.
Involuntary After-Tax Deductions You Didn’t Choose
Garnishments, support orders, and tax levies also come out after taxes, but you don’t get to opt out. Your employer receives a legal order and is required to comply. These are the deductions that catch people off guard.
Consumer Debt Garnishments
A creditor who wins a court judgment against you can garnish your wages to collect. Federal law caps ordinary consumer garnishments at the lesser of 25% of your disposable earnings, or the amount by which your weekly disposable earnings exceed 30 times the federal minimum wage. With the federal minimum at $7.25 an hour, that floor is $217.50 a week.6Office of the Law Revision Counsel. 15 USC 1673 – Restriction on Garnishment If your weekly disposable income is at or below $217.50, ordinary consumer debts can’t be garnished from your wages at all.7U.S. Department of Labor. Fact Sheet 30 – Wage Garnishment Protections of the Consumer Credit Protection Act
Child Support and Alimony
Support orders have priority over almost every other garnishment, and the ceilings are higher. If you’re supporting another spouse or dependent children, up to 50% of your disposable earnings can be withheld. If you’re not, that ceiling rises to 60%. An extra 5% can be garnished if you’re more than 12 weeks behind on payments.6Office of the Law Revision Counsel. 15 USC 1673 – Restriction on Garnishment An employer that receives an Income Withholding for Support order has to begin withholding promptly, and child support takes priority over other garnishments except an IRS tax levy that predates the support order.8Administration for Children and Families. Processing an Income Withholding Order or Notice
Federal Student Loan Garnishments
If you default on federal student loans, the Department of Education or its guaranty agencies can garnish up to 15% of your disposable pay without going to court first. This administrative garnishment authority comes from the Higher Education Act. You must get written notice at least 30 days before garnishment starts, and you have the right to request a hearing on the debt amount or the repayment terms.9Office of the Law Revision Counsel. 20 USC 1095a – Wage Garnishment Requirement
IRS Tax Levies
When you owe unpaid federal taxes, the IRS can send a levy directly to your employer using Form 668-W. IRS levies don’t follow the standard consumer garnishment percentages. Instead, the amount exempt from levy is calculated from your filing status and the number of dependents you claim, and everything above that exempt figure is subject to collection. Your employer gives you a Statement of Dependents and Filing Status to complete within three days of receiving the levy.10Internal Revenue Service. What if I Get a Levy Against One of My Employees, Vendors, Customers or Other Third Parties
The Minimum Wage Floor on Deductions
Federal law requires wages be paid “free and clear.” Under Department of Labor regulations, no deduction can push your effective pay below the federal minimum wage for a workweek if that deduction primarily benefits your employer. If your employer requires you to buy specific tools or uniforms, for instance, that expense can’t drop your hourly rate below $7.25.11eCFR. 29 CFR 531.35 The rule targets kickback arrangements where employees effectively hand part of their wages back to the boss.
This floor applies to employer-benefiting deductions. It doesn’t limit voluntary personal deductions like Roth contributions or supplemental insurance, and it doesn’t govern the recovery of an accidental overpayment, which is a separate category. Federal law generally lets an employer recoup an overpayment from future checks, though many states impose stricter limits on how much can be taken per pay period and whether your written consent is required.
Authorizing, Stopping, and Disputing a Deduction
Voluntary after-tax deductions require your written authorization before your employer can withhold anything. The authorization form should identify the purpose of the deduction and state either a fixed dollar amount or a percentage of your pay. Employers keep those forms on file as proof of your consent. To stop a voluntary deduction, submit a written revocation to your employer or HR, and the deduction should stop within one or two pay periods.
Involuntary deductions work differently. Your employer receives a legal order from a court, agency, or the IRS directing them to withhold a specific amount, and the order arrives with instructions the employer must follow or face penalties. For child support, the standardized Income Withholding for Support form triggers the obligation.8Administration for Children and Families. Processing an Income Withholding Order or Notice For tax debts, the IRS sends a Notice of Levy. You should get a copy of the order, or at minimum a notice that part of your wages is being redirected.
If a deduction appears on your stub that you didn’t authorize, or if a garnishment amount looks wrong, raise it with your payroll department in writing and keep copies of your pay stubs and any authorization forms. If your employer doesn’t fix it, you can file a complaint with your state labor department or the U.S. Department of Labor’s Wage and Hour Division. Employees can also sue under the Fair Labor Standards Act to recover back wages plus an equal amount in liquidated damages, along with attorney’s fees. The statute of limitations is two years for standard violations and three years for willful ones. Retaliating against you for filing a wage complaint is itself a federal violation.12U.S. Department of Labor. Fair Labor Standards Act Advisor
Reading Your Pay Stub to Check the Math
Most pay stubs split deductions into “pre-tax” and “post-tax” or “after-tax” sections, though the exact labels vary. Gross pay minus pre-tax deductions gives you your taxable wages. Taxable wages minus tax withholdings minus after-tax deductions gives you your net pay, which is what lands in your bank account.
When the numbers don’t line up with the last stub, the usual culprits are a mid-year W-4 change, hitting the Social Security wage cap partway through the year (which suddenly increases your take-home), a new garnishment order, or an insurance premium change during open enrollment. Comparing two consecutive stubs side by side usually surfaces the difference. When it doesn’t, your payroll or HR department has to explain what each line represents.