Federal Income Tax: What It Means for Employers

What it means in practice

What the tax is. Section 1 of the Internal Revenue Code says "there is hereby imposed on the taxable income" of individuals a tax set by rate tables, with separate tables for married couples filing jointly and surviving spouses, heads of household, unmarried individuals, and married individuals filing separately (26 U.S.C. 1). It is the employee's own tax, figured on the employee's return. The employer's part is collecting it in advance from wages. That collection process, including Form W-4, the Publication 15-T tables, deposits and Form 941, is explained on our federal income tax withholding page. This entry covers the tax itself and why it matters to payroll and HR.

Federal versus state "personal income tax." "Personal income tax" is a general name for a tax on an individual's income, and it can mean either the federal tax described here or a state's own tax. California's Employment Development Department, for example, describes California Personal Income Tax (PIT) as "a tax on the income of California residents and on income that nonresidents get within California," and Pennsylvania's Department of Revenue calls its levy the Pennsylvania personal income tax. IRS Publication 15 says its references to "income tax" apply only to federal income tax and tells employers to contact their state or local tax department for those rules. For the state side of payroll, see state withholding tax.

Gross income versus taxable income. The tax is not charged on gross pay. Section 61(a) defines gross income as "all income from whatever source derived," including "compensation for services, including fees, commissions, fringe benefits, and similar items." Section 63 then defines taxable income as gross income minus the deductions the law allows; for an individual who does not itemize, it starts from adjusted gross income and subtracts the standard deduction and certain other deductions. IRS Topic 401 adds two points that matter in payroll: amounts withheld for taxes, including income, Social Security and Medicare taxes, are treated as received and stay in gross income, while amounts withheld under certain salary reduction agreements are generally excluded from gross income even though they remain subject to Social Security and Medicare taxes. For the everyday payroll meaning of the term, see gross income.

Which pay is taxable. Publication 525 (2025) says that in most cases a person must include in gross income everything received in payment for personal services: wages, salaries, commissions, fees and tips, plus fringe benefits and stock options, and that an amount included in income is taxable unless specifically exempted by law. Publication 15-B (2026) puts the same rule in employer terms: any fringe benefit you provide is taxable and must be included in the recipient's pay unless the law specifically excludes it. Its 2026 exclusions include qualified parking and transit passes up to $340 a month each, dependent care assistance up to $7,500 ($3,750 for a married employee filing separately), educational assistance up to $5,250, and the cost of up to $50,000 of group-term life insurance coverage. Cash and cash equivalents such as gift cards are never excludable as de minimis benefits, and Publication 525 says a holiday turkey or ham is not income but cash or a gift certificate is wages regardless of the amount. The 2026 Form W-2 instructions tell employers to show total taxable wages, tips and other compensation in box 1, leaving out elective deferrals such as 401(k) contributions, and the federal income tax withheld in box 2.

2026 tax brackets. Rev. Proc. 2025-32 sets the 2026 tables. Single: 10% on taxable income up to $12,400; 12% over $12,400; 22% over $50,400; 24% over $105,700; 32% over $201,775; 35% over $256,225; 37% over $640,600. Married filing jointly: 10% up to $24,800; 12% over $24,800; 22% over $100,800; 24% over $211,400; 32% over $403,550; 35% over $512,450; 37% over $768,700. Head of household: 10% up to $17,700; 12% over $17,700; 22% over $67,450; 24% over $105,700; 32% over $201,750; 35% over $256,200; 37% over $640,600. Married filing separately follows the single table until the 37% rate, which starts over $384,350.

How brackets work. The IRS explains that when income moves into a higher bracket, "you don't pay the higher rate on your entire income," only on the part in the new bracket. The Rev. Proc. tables express this as a fixed amount plus a percentage of the excess over the bracket floor.

Standard deduction and other 2026 changes. For 2026 the standard deduction is $16,100 for single filers and married individuals filing separately, $32,200 for married couples filing jointly and $24,150 for heads of household, and personal exemptions remain at zero (IRS IR-2025-103). Age, blindness and dependent rules are on our standard deduction page. Publication 15 (2026) adds that P.L. 119-21 lets employees deduct up to $25,000 of qualified tips and up to $12,500 ($25,000 if married filing jointly) of qualified overtime compensation for tax years 2025 through 2028; the pay generally remains subject to Social Security and Medicare taxes, and the deduction is claimed on the return.

A pay-as-you-go tax. Publication 505 (2026) says the federal income tax "is a pay-as-you-go tax": the tax must be paid as income is earned, in one of two ways. Withholding is the first: the employer withholds from pay and the amount "is paid to the IRS in your name." Estimated tax is the second, used by people in business for themselves and for income such as dividends, interest, capital gains, rents and royalties; it also covers self-employment tax. For 2026 the estimated tax due dates are April 15, June 15 and September 15, 2026, and January 15, 2027. Section 31(a) allows the amount withheld during a calendar year as a credit against the employee's tax for the taxable year beginning in that year, which is how withholding is settled on the return.

How it differs from FICA. Publication 15 (2026) lists Social Security tax at 6.2% each for employer and employee on wages up to $184,500, and Medicare tax at 1.45% each with no wage base; IRS Topic 751 says only Social Security tax has a wage base limit. Federal income tax works differently on both counts. Its rates are graduated, apply to taxable income, and the top bracket has no ceiling. There is also no employer share: section 1 taxes the individual, and Publication 15 describes the income tax and the employee share of Social Security and Medicare taxes that an employer withholds as part of the employees' wages paid to the Treasury instead of to the employees. A 401(k) salary deferral also generally lowers income-taxable wages but not Social Security and Medicare wages (Topic 401). See FICA.

The employer's role, step by step. (1) Get a Form W-4 from each new employee; Publication 505 says an employee who gives none is treated as Single or Married filing separately with no other entries. (2) Decide which payments and benefits are taxable wages, using Publication 15-B for fringe benefits. (3) Withhold under Publication 15 and 15-T and deposit the tax as a trust fund tax; Publication 15 warns that the trust fund recovery penalty may apply if withheld income tax is not deposited or paid. (4) Furnish Form W-2. Section 6051(a) requires it by January 31 of the following year, and the 2026 Form W-2 instructions set February 1, 2027 for furnishing Copies B, C and 2 and for filing Copy A with the Social Security Administration. For 2026 the instructions add new box 12 codes: TP for cash tips reported to the employer and TT for qualified overtime compensation, which Publication 505 says employees use when figuring those deductions. (5) The employee then files. Topic 401 says employees must include all income and withholding from every Form W-2 on their return.

Filing deadline. Section 6072(a) requires calendar-year individual returns by April 15 of the following year. IRS Topic 301 says a due date that falls on a Saturday, Sunday or legal holiday moves to the next business day, that the 2025 return was due April 15, 2026, and that Form 4868 gives an automatic 6-month extension to file but not to pay. Under the same rule, 2026 returns are generally due April 15, 2027, a Thursday.

Why withholding rarely equals the final tax. Publication 505 says the income tax withheld from regular pay depends on the amount earned each payroll period, the payroll period, and the information on Form W-4. The tax on the return depends on the whole year. Publication 505 lists changes that move the final tax away from withholding: marriage, divorce, a birth or adoption, starting or stopping a second job, income not subject to withholding such as interest, dividends, capital gains and self-employment income, and changes in deductions or credits such as the child tax credit and the earned income credit. Two-job households and couples where both spouses work are "more likely to need to increase" withholding, and people who work only part of the year may have too much withheld. If too little is withheld, the employee owes tax and may owe interest and a penalty; if too much, the employee "will lose the use of that money" until the refund. Employees must give a new Form W-4 within 10 days after certain changes that leave withholding short for the rest of the year.

Underpayment penalty basics. Section 6654(a) adds an amount to the tax when an individual underpays estimated tax, figured with the section 6621 underpayment rate on the amount and period of the underpayment. IRS Topic 306 says most taxpayers avoid it if they owe less than $1,000 after withholding and refundable credits, or if withholding and estimated tax were at least 90% of the current year's tax or 100% of the prior year's, whichever is smaller. For 2026, Publication 505 substitutes 110% for 100% if 2025 adjusted gross income was over $150,000 ($75,000 married filing separately). Under section 6654(g), withholding is treated as paid in equal parts on each due date unless the taxpayer shows when it was actually withheld. Topic 306 says the IRS can waive the penalty for a casualty, disaster or other unusual circumstance, or after retirement at age 62 or later or disability where there was reasonable cause.

Example 1 (illustration): one job, full year. A single employee earns $60,000 in 2026 with no other income, deductions or credits. Taxable income is $60,000 - $16,100 = $43,900. Using the 2026 single table, the tax is $1,240 + 12% of $31,500 = $5,020, about 8.4% of wages, though the top rate reached is 12%. With a Single Form W-4 and no other entries, the Publication 15-T (2026) annual table also produces $5,020: $60,000 - $8,600 = $51,400, and the $19,900 to $57,900 row gives $1,240 + 12% of $31,500.

Example 2 (illustration): two earners. Spouses each earn $60,000 in 2026 and each gives a Form W-4 marked Married filing jointly, without checking Step 2. Each employer withholds on $60,000 - $12,900 = $47,100: $2,480 + 12% of $3,000 = $2,840, or $5,680 in total. Their joint taxable income is $120,000 - $32,200 = $87,800, and the tax is $2,480 + 12% of $63,000 = $10,040, leaving $4,360 not withheld before any credits. This is the multiple-jobs situation Step 2 of Form W-4 addresses.

Example 3 (illustration): crossing a bracket. A single filer with 2026 taxable income of $110,000 owes $17,966 + 24% of $4,300 = $18,998. Only the $4,300 above $105,700 is taxed at 24%.

Where states differ. State income taxes are separate and follow each state's law. Two examples, not a survey: Pennsylvania's Department of Revenue says its personal income tax is levied at 3.07% on taxable income of residents and nonresidents, has no standard deduction or personal exemption, and is collected partly through employer withholding. California's EDD says PIT is withheld based on the employee's Form DE 4, with no taxable wage limit and no maximum tax. Check your state revenue agency.

Questions employers ask. Does the business pay federal income tax on employees' wages? No employer share exists, but the employer must withhold and pay over the employee's tax (Publication 15). Can we refund over-withholding caused by an outdated Form W-4? Publication 505 says the employer cannot repay tax already withheld for that reason; the employee claims it on the return. Are tips and overtime now exempt? No. They generally remain subject to Social Security and Medicare taxes; the 2025-2028 deductions reduce taxable income on the return (Publication 15).

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Related terms

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