The deductions on your paycheck fall into three groups: taxes your employer is required to withhold and send to the government, benefits you signed up for through your employer, and any court-ordered payments like child support or wage garnishments. Some come out before income tax is calculated, which lowers your taxable wages, and some come out after. Every line on your stub belongs to one of these buckets.
Taxes Your Employer Must Withhold
The largest deductions on most paychecks are taxes. Your employer has no discretion here — federal law requires the withholding and sends the money to the IRS on your behalf.1Office of the Law Revision Counsel. 26 USC 3402 – Income Tax Collected at Source
Federal Income Tax
How much federal income tax comes out of each check depends on what you put on Form W-4: your filing status, dependents, and any extra amount you asked to be withheld. If you never filed a W-4, your employer withholds as though you’re single with no adjustments, which usually pulls more than needed.2Internal Revenue Service. Withholding Compliance Questions and Answers
Federal rates run from 10% to 37% in graduated brackets, so only the portion of your income in the top bracket is taxed at the top rate.3Internal Revenue Service. Federal Income Tax Rates and Brackets Bonuses and commissions get treated differently. Supplemental pay is generally withheld at a flat 22%, and anything above $1 million in supplemental pay during a calendar year is withheld at 37%.4Internal Revenue Service. Publication 15 (2026) Employers Tax Guide That flat rate is why a bonus check can look thinner than expected.
The IRS offers a free Tax Withholding Estimator to help you check whether you’re on track for the year.5Internal Revenue Service. Tax Withholding Estimator
Social Security and Medicare (FICA)
Two more federal deductions come out of every paycheck, and unlike income tax, the rates are fixed. Social Security tax is 6.2% of gross wages up to an annual cap — $184,500 in 2026.6Social Security Administration. 2026 Cost-of-Living Adjustment (COLA) Fact Sheet Once you hit that wage cap, Social Security withholding stops for the rest of the year. Change jobs mid-year and each new employer starts the count from zero, which can cause overwithholding; you get the excess back when you file.7Office of the Law Revision Counsel. 26 USC 3101 – Rate of Tax
Medicare tax is 1.45% of all wages with no cap. High earners pay an extra 0.9% Medicare surtax on wages above $200,000 for single filers or $250,000 for joint filers.8Internal Revenue Service. Questions and Answers for the Additional Medicare Tax Your employer starts withholding that extra 0.9% once your own wages cross $200,000, regardless of filing status, so joint filers whose combined income falls below $250,000 may get a credit back at tax time.
Your employer separately pays a matching 6.2% and 1.45% on top of what comes out of your check. That match doesn’t appear on your stub.
State and Local Taxes
Most states impose an income tax withheld the same way federal tax is. Some states use a flat rate, others use brackets, and a handful have no state income tax. Certain cities and counties add their own local income tax on top. Each shows up as its own line.
Some states also require paycheck contributions to disability insurance or paid family leave programs. These usually run between roughly 0.2% and 1.3% of wages, often capped annually. If you see an acronym like SDI or PFML on your stub, it’s one of these state-mandated programs.
Pre-Tax Benefit Deductions
Pre-tax deductions come out of your gross pay before federal income tax is calculated. That order matters: every dollar of pre-tax deduction is a dollar you don’t pay income tax on that year, which is what makes employer benefits cheaper than buying the same thing on your own.
Health, dental, and vision premiums. If your employer offers a group health plan, your share of the premium is usually deducted pre-tax through a cafeteria plan.9Internal Revenue Service. Publication 15-B (2026) Employers Tax Guide to Fringe Benefits The amount depends on your coverage tier and how much your employer subsidizes. Someone in the 22% bracket who pays $200 per paycheck toward health insurance saves about $44 in federal income tax each pay period compared with paying after tax.
Traditional 401(k) contributions. If you earn $50,000 and contribute $3,000 to a traditional 401(k), your federally taxable income drops to $47,000.9Internal Revenue Service. Publication 15-B (2026) Employers Tax Guide to Fringe Benefits You’ll owe income tax when you withdraw in retirement. The 2026 base contribution limit is $24,500, with additional catch-up room for workers 50 and older.10Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500 One important boundary: traditional 401(k) contributions reduce federal and state income tax, but FICA still applies to the full amount. Your Social Security and Medicare withholding won’t go down because you contributed.
HSA and FSA contributions. An HSA is available only if you have a qualifying high-deductible health plan. For 2026, the contribution limit is $4,400 for self-only coverage or $8,750 for family coverage, and the funds roll over indefinitely.11Internal Revenue Service. IRS Notice 2026-5 – Expanded Availability of Health Savings Accounts A health care FSA has a 2026 limit of $3,400 and generally must be spent within the plan year or forfeited, though many employers offer a grace period or a small carryover. Both accounts reduce your taxable income dollar for dollar.
After-Tax Deductions
After-tax deductions come out after income taxes are calculated, so they don’t lower your current year’s taxable income.
The most common one is a Roth 401(k) contribution. You pay taxes on the money now, and qualified withdrawals in retirement come out tax-free, including any investment gains. The same annual limits apply as with a traditional 401(k) — $24,500 base for 2026 — but there’s no upfront tax break.10Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500
Other after-tax lines you might see include employer-sponsored life insurance premiums for coverage above the first $50,000 (the cost of coverage beyond that amount is taxable), long-term disability insurance in some plans, and union dues. These stay consistent unless you change them at open enrollment or through a qualifying life event.
Wage Garnishments and Court-Ordered Deductions
Involuntary deductions happen when a court or government agency orders your employer to redirect part of your wages. You don’t choose them, and your employer must comply.
The most common are child support, court judgments for unpaid debts, and defaulted federal student loans. Child support takes priority over other garnishments. Federal student loan garnishments don’t need a court hearing — the Department of Education can order withholding administratively.
Federal law caps how much creditors can take. For ordinary consumer debts, the maximum is the lesser of 25% of your disposable earnings or the amount by which your weekly disposable earnings exceed $217.50, which is 30 times the $7.25 federal minimum wage.12Office of the Law Revision Counsel. 15 USC 1673 – Restriction on Garnishment If your disposable pay is below $217.50 per week, ordinary creditors can’t garnish anything.
Child support garnishments can reach higher: 50% of disposable earnings if you’re supporting another spouse or child, 60% if you’re not, with an extra 5% if you’re more than 12 weeks behind.12Office of the Law Revision Counsel. 15 USC 1673 – Restriction on Garnishment
How to Read the Deductions on Your Pay Stub
Most stubs show two columns for each deduction: the current pay period and the year-to-date total. The year-to-date column is the one to watch, because it’s the number you’ll match against your W-2 in January.
On the W-2, Box 1 shows your taxable wages after pre-tax deductions have already been subtracted. Box 2 shows federal income tax withheld. Boxes 3 and 5 show Social Security and Medicare wages, and Boxes 4 and 6 show the corresponding taxes. If your year-to-date stub figures don’t line up with the W-2, contact payroll before you file.
Box 12 uses letter codes for specific deductions. The ones you’re most likely to see are Code D for traditional 401(k) contributions, Code W for employer HSA contributions, Code DD for the total cost of employer-sponsored health coverage, and Code AA for Roth 401(k) contributions.13Internal Revenue Service. Form W-2 Reference Guide for Box 12 Codes Code DD is informational only. It doesn’t mean that amount is taxable — the IRS just requires employers to report the total cost of group health coverage.
What to Do If a Deduction Looks Wrong
Payroll errors are common. A benefits enrollment might not have processed, a garnishment might not have ended when it should, or a withholding amount might not match what you put on your W-4. Compare your pay stub against your most recent W-4, your benefits enrollment confirmation, and any court orders on file. If the numbers don’t match, start with human resources or payroll. Most errors are clerical and get fixed quickly once someone flags them.
Some deductions are flatly illegal. Your employer can’t withhold money for things like cash register shortages, broken equipment, or uniform costs if doing so would push your effective pay below the minimum wage.14eCFR. Title 29 Section 4.168 – Wage Payments, Deductions From Wages Paid Deductions must be required by law, ordered by a court, or authorized by you in writing for a specific purpose. If your employer is taking money you didn’t agree to and can’t explain, you can file a complaint with the Department of Labor’s Wage and Hour Division online or by calling 1-866-487-9243. The agency typically contacts you within two business days and investigates if warranted.15Worker.gov. Filing a Complaint With the U.S. Department of Labors Wage and Hour Division (WHD)