Mandatory payroll deductions are the amounts your employer is legally required to take out of your paycheck before you see any of it. They fall into a short list: federal income tax, Social Security and Medicare taxes (FICA), state and local income taxes where they apply, state-run insurance program contributions in a handful of states, and any court-ordered garnishments. None of these are optional on your end. Your employer has no authority to skip them because you’d prefer a bigger check.
Federal Income Tax
Every employer paying wages must withhold federal income tax from each paycheck and send it to the IRS.1Office of the Law Revision Counsel. 26 USC 3402 – Income Tax Collected at Source The system is pay-as-you-go: the government collects tax throughout the year rather than waiting for one annual payment.2Internal Revenue Service. Tax Withholding for Individuals
How much comes out of each paycheck depends on what you report on Form W-4, the Employee’s Withholding Certificate. You fill it out when you start a job, and you can update it any time your situation changes. Your filing status, dependents, and any additional income or deductions you list all feed the calculation your employer runs against the IRS withholding tables.
For tax year 2026, federal income tax rates range from 10% to 37%. The standard deduction is $16,100 for single filers and $32,200 for married couples filing jointly.3Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026, Including Amendments From the One, Big, Beautiful Bill Those numbers shape what you ultimately owe at filing time; the per-paycheck withholding is a running estimate driven by your W-4.
Social Security and Medicare (FICA)
FICA is separate from income tax and funds retirement, disability, and healthcare programs. The rates are fixed by statute and don’t shift with your W-4.4Office of the Law Revision Counsel. 26 USC 3101 – Rate of Tax
Social Security tax runs at 6.2% on wages up to an annual cap called the wage base. For 2026, that cap is $184,500, and earnings above it are not subject to the 6.2% deduction.5Social Security Administration. Contribution and Benefit Base Medicare tax runs at 1.45% on all wages with no cap. If you earn more than $200,000 as a single filer, or $250,000 married filing jointly, an additional 0.9% Medicare surtax kicks in on earnings above that threshold, and that surtax comes entirely from the employee side.4Office of the Law Revision Counsel. 26 USC 3101 – Rate of Tax These withholdings apply to nearly all wage earners in the private sector regardless of whether you’ll eventually collect Social Security benefits.
State and Local Income Tax
Most states impose their own income tax on wages, and your employer withholds it alongside federal tax. Eight states collect no personal income tax at all: Alaska, Florida, Nevada, South Dakota, Tennessee, Texas, Washington, and Wyoming. Everywhere else, expect a state income tax line on your pay stub.
Rates and structures vary widely. Some states use a flat rate; others use graduated brackets similar to the federal system. Your employer calculates the withholding from the state’s rules and any state withholding form you file. Some cities and counties add a local income tax on top, usually a small percentage funding municipal services. Where local law requires it, the deduction is mandatory and your employer cannot waive it.
Living in one state and working in another complicates things. Some states have reciprocal agreements that prevent double taxation; others don’t. In those cases you may need to file returns in both states and claim a credit for taxes paid to the work state. Whatever the arrangement, the withholding your employer performs under state or local law is as mandatory as federal tax.
State-Mandated Insurance Contributions
A growing number of states require payroll deductions for state-run insurance programs that cover short-term disability, paid family leave, or both. These are separate from income taxes and fund partial wage replacement when you can’t work due to illness, injury, or the need to care for a family member.
The exact percentage varies by state and is adjusted periodically based on each program’s funding needs. Contributions typically apply to wages up to a state-defined cap and appear as their own line on your pay stub. Some programs are funded entirely by employee contributions; others split the cost with employers. If you work in a state with one of these programs, the deduction is mandatory. You cannot opt out any more than you can opt out of FICA.
Court-Ordered Wage Garnishments
When a court or government agency orders your employer to redirect part of your pay to a creditor, that garnishment becomes another mandatory deduction. Common triggers include unpaid child support, alimony, defaulted student loans, and tax debts. Once your employer receives a valid order, compliance isn’t optional; an employer who ignores it can be forced to pay the debt from its own funds.
Ordinary Debts
Federal law caps how much can be taken for most consumer debts. For ordinary garnishments such as credit card judgments, weekly withholding cannot exceed the lesser of 25% of your disposable earnings or the amount by which your disposable earnings exceed 30 times the federal minimum wage ($7.25 per hour as of 2026).6Office of the Law Revision Counsel. 15 USC 1673 – Restriction on Garnishment “Disposable earnings” means what’s left after legally required deductions like taxes and FICA, not your gross pay. In practice, if your weekly disposable earnings are $217.50 or less, nothing can be garnished for ordinary debts. Between $217.50 and $290, only the amount above $217.50 is subject to garnishment. At $290 or more, the 25% cap applies.7U.S. Department of Labor. Fact Sheet 30 – Wage Garnishment Protections of the Consumer Credit Protection Act
Child Support and Alimony
The 25% cap does not apply to child support or alimony. Support orders can take substantially more. If you’re currently supporting another spouse or child beyond the one covered by the order, the cap is 50% of your disposable earnings. If you’re not supporting anyone else, it rises to 60%. When the support order is more than 12 weeks in arrears, add another 5%, taking the maximum to 55% or 65%.6Office of the Law Revision Counsel. 15 USC 1673 – Restriction on Garnishment Federal and state tax debts are also exempt from the standard garnishment caps.
Defaulted Student Loans
Defaulted federal student loans follow their own rules. The federal government can garnish up to 15% of your disposable pay through an administrative process. Unlike most creditors, the Department of Education does not always need a court order to begin garnishing, though borrowers must receive notice and a chance to contest before withholding starts.
Being Fired Over a Garnishment
Federal law prohibits your employer from firing you because your wages are being garnished for a single debt. An employer who violates that protection faces a fine of up to $1,000, up to one year in prison, or both.8Office of the Law Revision Counsel. 15 USC 1674 – Restriction on Discharge From Employment by Reason of Garnishment The protection covers one garnishment only. It does not extend to employees with garnishments for two or more separate debts.
When Your Paycheck Can’t Cover Everything
Occasionally a paycheck is too small to cover every mandatory withholding, say a week with very few hours or one with heavy garnishments layered on. When that happens, deductions follow a priority order. Federal taxes and FICA come first because the government’s claim takes precedence. State and local taxes follow. Court-ordered support like child support comes next, ahead of commercial garnishments and any voluntary deductions. If there’s not enough left after the higher-priority items, lower-priority deductions get reduced or skipped for that pay period.
Your Liability for a False W-4
Your employer handles the mechanics, but you have your own legal obligation to give accurate information on your W-4. Filing a W-4 with false information to reduce your withholding carries a $500 civil penalty per false statement.9Office of the Law Revision Counsel. 26 USC 6682 – False Information With Respect to Withholding The IRS can waive the penalty if your total tax liability for the year is covered by credits and estimated payments, but gaming the W-4 to avoid withholding rarely pays off. You still owe the full tax at filing time, plus potential interest and underpayment penalties on top.