Income tax

Income tax in the United States

The federal government of the United States imposes a progressive tax on the taxable income of individuals, partnerships, companies, corporations, trusts, decedents' estates, and certain bankruptcy estates. Some state and municipal governments also impose income taxes. The first Federal income tax was imposed (under Article I, section 8, clause 1 of the U.S. Constitution) during the Civil War, then again in the 1890s, and again after the Sixteenth Amendment was ratified in 1913. Current income taxes are imposed under these constitutional provisions and various sections of Subtitle A of the Internal Revenue Code of 1986, as amended, including 26 U.S.C. § imposing income tax on the taxable income of individuals, estates and trusts) and 26 U.S.C. § 11 (imposing income tax on the taxable income of corporations).

Income tax basics
While U.S. income tax law is very complex, the underlying idea is relatively easy to understand. Simplifying greatly, gross income is all income from all sources (§ 61) less any exclusions (§ 101 et seq.). An exclusion is something that Congress has effectively said a taxpayer need not include in his or her income for tax purposes, such as employer-paid health insurance (§ 106) or interest from tax-exempt bonds (§ 103). Exclusions, often referred to as deductions, are a matter of legislative grace; that is, taxpayers may not exclude, or deduct, from gross income any item which Congress has not specifically allowed.
For individuals, Adjusted Gross Income (AGI) is gross income less any above-the-line deductions (§ 62). Above-the-line deductions are listed in § 62 and include trade or business deductions, alimony (§ 215), and moving expenses (§ 217). Taxable income is AGI less (1) itemized deductions or the applicable standard deduction, whichever is greater, and (2) a deduction for any allowable personal exemptions for the taxpayer, the taxpayer's spouse (if filing jointly), and the taxpayer's dependents. (In certain cases involving higher income taxpayers, the allowed personal exemptions may be reduced or even eliminated.)
Non-itemizers take the standard deduction. Itemized deductions include any deduction not listed in § 62 such as charitable contributions (§ 170) and certain medical expenses (§ 213). Taxable income is then multiplied by the appropriate tax rate to arrive at the tax due. Tax credits such as the Earned Income Tax Credit (§ 32) or the Child Tax Credit (§ 24) lower the tax owed on a dollar-for-dollar basis. This means tax credits are more valuable than deductions of the same amount, because deductions are applied before the tax rate, while credits are applied after. For instance, with a 35% tax rate, a deduction of $100 would save only $35 of taxes, while a $100 credit would save $100 worth of taxes.

Types of income
For tax purposes, income can be divided in a variety of ways. The first division is between ordinary income and capital gains. Ordinary income includes compensation for personal services such as wages and salaries, business profit, dividends from stock shares, and interest income from invested funds while capital gain generally comes from the sale of investment property. Congress has typically shown a preference for long-term investment by having a capital gains tax rate lower than the ordinary income rate. However, only long-term capital gains get preferential treatment; short-term capital gains (from property held for one year or less) are taxed at the same rate as ordinary income. Added complications come from various distinctions within each category. For instance, qualified dividends, which were previously taxed at ordinary income rates (as non-qualified dividends currently are), are currently taxed at long-term capital gain rates until 2011 under the Jobs and Growth Tax Relief Reconciliation Act of 2003, and within long-term capital gains, gains on certain real estate, collectibles, and small business stock each have their own tax rates. The rules for offsetting capital losses with gains (whether capital or ordinary) add further complications. In ordinary usage, when someone speaks of their "tax rate", they typically are referring to their marginal tax rate for ordinary income.
Another important distinction in types of income is income from passive activities versus non-passive activities (§ 469), an attempt to curb tax shelters used by taxpayers not directly involved with an activity other than as an investor ("passive").

An individual's marginal income tax bracket depends upon his income and his tax-filing classification. As of 2008, there are six tax brackets for ordinary income (ranging from 10% to 35%) and four classifications: single, married filing jointly (or qualified widow or widower), married filing separately, and head of household.

An individual pays tax at a given bracket only for each dollar within that bracket's range. For example, a single taxpayer who earned $10,000 in 2009 would be taxed 10% of each dollar earned from the 1st dollar to the 8,350th dollar (10% × $8,350 = $835.00), then 15% of each dollar earned from the 8,351th dollar to the 10,000th dollar (15% × $1,650 = $247.50), for a total of $1,082.50. Notice this amount ($1,082.50) is lower than if the individual had been taxed at 15% on the full $10,000 (for a tax of $1,500). This is because the individual's marginal rate (the percentage tax on the last dollar earned, here 15%) has no effect on the income taxed at a lower bracket (here the first $8,350 of income taxed at 10%). This ensures that every rise in a person's pre-tax salary results in an increase of his after-tax salary.

However, taxpayers are not taxed on every dollar they make. For 2009, single and married filing separate taxpayers are allowed a standard deduction of $5,700. Married filing jointly and surviving widow(er)s are allowed $11,340 and head of household taxpayers are allowed $8,350. Taxpayers over 65 or blind are given an additional $1,100 standard deduction ($2,200 if over 65 and blind). A taxpayer may choose to take the standard deduction or they may itemize their deductions if the amount of itemized deductions is greater than the standard deduction.
Taxpayers are also allowed a personal exemption depending on their filing status. The personal exemption amount in 2009 is $3,650 per person.

Claiming deductions may reduce an individual's tax liability by a rate equal to the marginal tax rate of their particular tax bracket, with a corresponding reduction in returns as the individual crosses in to a lower tax bracket. For example, if an individual is able to increase the amount of their deduction by $1000 with a last-minute donation to a charitable organization, and the individual's adjusted gross income is $500 into the 25% marginal tax bracket, the donation will reduce the tax liability of the individual by ($500 × 25%) + ($500 × 15%) = $200.

The effective tax rates corresponding to the definitions above are shown in the accompanying graph.
Short-term capital gains are taxed as ordinary income rates as listed above. Long-term capital gains have lower rates corresponding to an individual’s marginal ordinary income tax rate, with special rates for a variety of capital goods
Example of a tax computation
Income tax for year 2009:
Single taxpayer, no children, under 65 and not blind taking standard deduction;
$40,000 gross income - $5,700 standard deduction - $3,650 personal exemption = $30,650 taxable income
$8,350 × 10% = $835.00
($30,650 - $8,350) = $22,300.00 x 15% = $3,345.00
Total income tax = $4,180.00 (10.45% effective tax)
Note that in addition to income tax, a wage earner would also have to pay FICA (payroll) tax (and an equal amount of FICA tax must be paid by the employer):
$40,000 (adjusted gross income)
$40,000 × 6.2% = $2,480 (Social Security portion)
$40,000 × 1.45% = $580 (Medicare portion)
Total FICA tax = $3,060 (7.65% of income)
Total federal tax of individual = $7,240.00 (18.10% of income)
Further information: Rate schedule (federal income tax)

Filing income taxes
April 15 is the deadline for individual taxpayers who are required to file income tax forms to do so. The IRS has reached agreements with various private companies allowing taxpayers who earn less than $56,000 to file taxes electronically for free. In 2008, 57% of taxpayers filed electronically, significantly reducing the last-minute rush at post offices.These companies may charge to file state income tax returns.

Legal history
Main article: United States income tax (legal history)
See also: Taxation history of the United States#Income tax
Article I, Section 8, Clause 1 of the United States Constitution (the "Taxing and Spending Clause"), specifies Congress's power to impose "Taxes, Duties, Imposts and Excises," but Article I, Section 8 requires that, "Duties, Imposts and Excises shall be uniform throughout the United States."
In addition, the Constitution specifically limited Congress' ability to impose direct taxes, by requiring Congress to distribute direct taxes in proportion to each state's census population. It was thought that head taxes and property taxes (slaves could be taxed as either or both) were likely to be abused, and that they bore no relation to the activities in which the federal government had a legitimate interest. The fourth clause of section 9 therefore specifies that, "No Capitation, or other direct, Tax shall be laid, unless in Proportion to the Census or enumeration herein before directed to be taken."

Taxation was also the subject of Federalist No. 33 penned secretly by the Federalist Alexander Hamilton under the pseudonym Publius. In it, he explains that the wording of the "Necessary and Proper" clause should serve as guidelines for the legislation of laws regarding taxation. The legislative branch is to be the judge, but any abuse of those powers of judging can be overturned by the people, whether as states or as a larger group.

The courts have generally held that direct taxes are limited to taxes on people (variously called "capitation", "poll tax" or "head tax") and property. All other taxes are commonly referred to as "indirect taxes," because they tax an event, rather than a person or property per se. What seemed to be a straightforward limitation on the power of the legislature based on the subject of the tax proved inexact and unclear when applied to an income tax, which can be arguably viewed either as a direct or an indirect tax.

Early Federal income taxes
In order to help pay for its war effort in the American Civil War, the United States government imposed its first personal income tax, on August 5, 1861, as part of the Revenue Act of 1861 (3% of all incomes over US $800) This tax was repealed and replaced by another income tax in 1862.

In 1894, Democrats in Congress passed the Wilson-Gorman tariff, which imposed the first peacetime income tax. The rate was 2% on income over $4000, which meant fewer than 10% of households would pay any. The purpose of the income tax was to make up for revenue that would be lost by tariff reductions.

In 1895 the United States Supreme Court, in its ruling in Pollock v. Farmers' Loan & Trust Co., held a tax based on receipts from the use of property to be unconstitutional. The Court held that taxes on rents from real estate, on interest income from personal property and other income from personal property (which includes dividend income) were treated as direct taxes on property, and therefore had to be apportioned. Since apportionment of income taxes is impractical, this had the effect of prohibiting a federal tax on income from property. The power to tax real and personal property, or that such was a direct tax, was not denied by the Constitution. Due to the political difficulties of taxing individual wages without taxing income from property, a federal income tax was impractical from the time of the Pollock decision until the time of ratification of the Sixteenth Amendment (below).

Ratification of the Sixteenth Amendment
In response, Congress proposed the Sixteenth Amendment (ratified by the requisite number of states in 1913, which states:
The Congress shall have power to lay and collect taxes on incomes, from whatever source derived, without apportionment among the several States, and without regard to any census or enumeration.
The Supreme Court in Brushaber v. Union Pacific Railroad, 240 U.S. 1 (1916), indicated that the amendment did not expand the federal government's existing power to tax income (meaning profit or gain from any source) but rather removed the possibility of classifying an income tax as a direct tax on the basis of the source of the income. The Amendment removed the need for the income tax to be apportioned among the states on the basis of population. Income taxes are required, however, to abide by the law of geographical uniformity.

Some tax protesters and others opposed to income taxes cite what they contend is evidence that the Sixteenth Amendment was never "properly ratified," based in large part on materials sold by William J. Benson. In December 2007, Benson's "Defense Reliance Package" containing his non-ratification argument which he offered for sale on the internet, was ruled by a federal court to be a "fraud perpetrated by Benson" that had "caused needless confusion and a waste of the customers' and the IRS' time and resources." The court stated: "Benson has failed to point to evidence that would create a genuinely disputed fact regarding whether the Sixteenth Amendment was properly ratified or whether United States Citizens are legally obligated to pay federal taxes." See also Tax protester Sixteenth Amendment arguments.

Modern interpretation of the power to tax incomes
The modern interpretation of the Sixteenth Amendment taxation power can be found in Commissioner v. Glenshaw Glass Co. 348 U.S. 426 (1955). In that case, a taxpayer had received an award of punitive damages from a competitor for antitrust violations and sought to avoid paying taxes on that award. The Court observed that Congress, in imposing the income tax, had defined gross income, under the Internal Revenue Code of 1939, to include:

gains, profits, and income derived from salaries, wages or compensation for personal service . . . of whatever kind and in whatever form paid, or from professions, vocations, trades, businesses, commerce, or sales, or dealings in property, whether real or personal, growing out of the ownership or use of or interest in such property; also from interest, rent, dividends, securities, or the transaction of any business carried on for gain or profit, or gains or profits and income derived from any source whatever.

(Note: The Glenshaw Glass case was an interpretation of the definition of "gross income" in section 22 of the Internal Revenue Code of 1939. The successor to section 22 of the 1939 Code is section 61 of the current Internal Revenue Code of 1986, as amended.)

The Court held that "this language was used by Congress to exert in this field the full measure of its taxing power", id., and that "the Court has given a liberal construction to this broad phraseology in recognition of the intention of Congress to tax all gains except those specifically exempted."

The Court then enunciated what is now understood by Congress and the Courts to be the definition of taxable income, "instances of undeniable accessions to wealth, clearly realized, and over which the taxpayers have complete dominion." Id. at 431. The defendant in that case suggested that a 1954 rewording of the tax code had limited the income that could be taxed, a position which the Court rejected, stating:

The definition of gross income has been simplified, but no effect upon its present broad scope was intended. Certainly punitive damages cannot reasonably be classified as gifts, nor do they come under any other exemption provision in the Code. We would do violence to the plain meaning of the statute and restrict a clear legislative attempt to bring the taxing power to bear upon all receipts constitutionally taxable were we to say that the payments in question here are not gross income.

Tax statutes passed after the ratification of the Sixteenth Amendment in 1913 are sometimes referred to as the "modern" tax statutes. Hundreds of Congressional acts have been passed since 1913, as well as several codifications (i.e., topical reorganizations) of the statutes (see Codification).

In Central Illinois Public Service Co. v. United States, 435 U.S. 21 (1978), the U.S. Supreme Court confirmed that wages and income are not identical as far as taxes on income are concerned, because income not only includes wages, but any other gains as well. The Court in that case noted that in enacting taxation legislation, Congress "chose not to return to the inclusive language of the Tariff Act of 1913, but, specifically, 'in the interest of simplicity and ease of administration,' confined the obligation to withhold [income taxes] to 'salaries, wages, and other forms of compensation for personal services'" and that "committee reports ... stated consistently that 'wages' meant remuneration 'if paid for services performed by an employee for his employer'".

Other courts have noted this distinction in upholding the taxation not only of wages, but also of personal gain derived from other sources, recognizing some limitation to the reach of income taxation. For example, in Conner v. United States, 303 F. Supp. 1187 (S.D. Tex. 1969), aff’d in part and rev’d in part, 439 F.2d 974 (5th Cir. 1971), a couple had lost their home to a fire, and had received compensation for their loss from the insurance company, partly in the form of hotel costs reimbursed. The court acknowledged the authority of the IRS to assess taxes on all forms of payment, but did not permit taxation on the compensation provided by the insurance company, because unlike a wage or a sale of goods at a profit, this was not a gain. As the Court noted, "Congress has taxed income, not compensation".

By contrast, other courts have interpreted the Constitution as providing even broader taxation powers for Congress. In Murphy v. IRS, the United States Court of Appeals for the District of Columbia Circuit upheld the Federal income tax imposed on a monetary settlement recovery that the same court had previously indicated was not income, stating: "[a]lthough the 'Congress cannot make a thing income which is not so in fact,' [ . . . ] it can label a thing income and tax it, so long as it acts within its constitutional authority, which includes not only the Sixteenth Amendment but also Article I, Sections 8 and 9.

Similarly, in Penn Mutual Indemnity Co. v. Commissioner, the United States Court of Appeals for the Third Circuit indicated that Congress could properly impose the Federal income tax on a receipt of money, regardless of what that receipt of money is called:

It could well be argued that the tax involved here [an income tax] is an "excise tax" based upon the receipt of money by the taxpayer. It certainly is not a tax on property and it certainly is not a capitation tax; therefore, it need not be apportioned. [ . . . ] Congress has the power to impose taxes generally, and if the particular imposition does not run afoul of any constitutional restrictions then the tax is lawful, call it what you will.

Tax rates in history

History of top rates

In 1913, the top tax rate was 7% on incomes above $500,000 ($10 million 2007 dollars)
.
During World War I, the top rate rose to 77% and the income threshold to be in this top bracket increased to $1,000,000 ($16 million 2007 dollars); after the war, the top rate was scaled down to a low of 24% and the income threshold for paying this rate fell to a low of $100,000 ($1 million 2007 dollars).

During the Great Depression and World War II, the top income tax rate rose from pre-war levels. In 1939, the top rate was 75% applied to incomes above $5,000,000 ($75 million 2007 dollars). During 1944 and 1945, the top rate was its all-time high at 94% applied to income above $200,000.

Since 1964, the threshold for paying top income tax rate has generally been between $200,000 and $400,000. The one exception is the period from 1982-1992 when the top income tax brackets were removed and incomes above around $100,000 (varies by year) paid the top rate. From 1988-1990, the threshold for paying the top rate was even lower, with incomes above $29,750 to $32,450 ($51,000 2007 dollars) paying the top rate of 28% in those years.

History of progressivity in federal income tax
The federal income tax rates in the United States have varied widely since 1913. For example, in 1954 the Congress imposed a federal income tax on individuals, with the tax imposed in layers of 24 income brackets at tax rates ranging from 20% to 91% (for a chart, see Internal Revenue Code of 1954). Here is a partial history of changes in the U.S. federal income tax rates for individuals (and the income brackets) since 1913

Hauser's Law
Hauser's Law is a theory that states that in the United States, federal tax revenues will always be equal to approximately 19.5% of GDP, regardless of what the top marginal tax rate is. The theory was first suggested in 1993 by Kurt Hauser, a San Francisco investment economist, who wrote at the time, "No matter what the tax rates have been, in postwar America tax revenues have remained at about 19.5% of GDP." In a May 20, 2008 editorial in the Wall St. Journal, David Ranson published a graph showing that even though the top marginal tax rate of federal income tax had varied between a low of 28% to a high of 91% between 1950 and 2007, federal tax revenues had indeed constantly remained at about 19.5% of GDP. Critics of Hauser's Law, such as Zubin Jelveh in a Wall St. Journal editorial, point out that tax revenues have fallen as top income rates declined if you don't include Social Security revenues. Similarly, other changes in tax rates and the income threshold for paying those rates are expected to impact tax revenues and should be considered when analyzing the relationship between tax-rates and tax revenues.

Sources of U.S. income tax laws
United States income tax law comes from a number of sources. These sources have been divided into three tiers as follows:
Tier 1
United States Constitution
Internal Revenue Code (IRC) (legislative authority, written by the United States Congress through legislation)
Treasury regulations
Federal court opinions (judicial authority, written by courts as interpretation of legislation)
Treaties (executive authority, written in conjunction with other countries)
Tier 2
Agency interpretative regulations (executive authority, written by the Internal Revenue Service (IRS) and Department of the Treasury), including:
Final, Temporary and Proposed Regulations promulgated under IRC § 7805;
Treasury Notices and Announcements;
Public Administrative Rulings (IRS Revenue Rulings, which provide informal guidance on specific questions and are binding on all taxpayers)
Tier 3
Legislative History
Private Administrative Rulings (private parties may approach the IRS directly and ask for a Private Letter Ruling on a specific issue - these rulings are binding only on the requesting taxpayer).
Where conflicts exist between various sources of tax authority, an authority in Tier 1 outweighs an authority in Tier 2 or 3. Similarly, an authority in Tier 2 outweighs an authority in Tier 3.


Where conflicts exist between two authorities in the same tier, the "last-in-time rule" is applied. As the name implies, the "last-in-time rule" states that the authority that was issued later in time is controlling.
Regulations and case law serve to interpret the statutes. Additionally, various sources of law attempt to do the same thing. Revenue Rulings, for example, serves as an interpretation of how the statutes apply to a very specific set of facts. Treaties serve in an international realm.

The complexity of the U.S. income tax laws
Even venerable legal scholars like Judge Learned Hand have expressed amazement and frustration with the complexity of the U.S. income tax laws. In the article, Thomas Walter Swan, 57 Yale Law Journal No. 2, 167, 169 (December 1947), Judge Hand wrote:

In my own case the words of such an act as the Income Tax… merely dance before my eyes in a meaningless procession: cross-reference to cross-reference, exception upon exception — couched in abstract terms that offer [me] no handle to seize hold of [and that] leave in my mind only a confused sense of some vitally important, but successfully concealed, purport, which it is my duty to extract, but which is within my power, if at all, only after the most inordinate expenditure of time. I know that these monsters are the result of fabulous industry and ingenuity, plugging up this hole and casting out that net, against all possible evasion; yet at times I cannot help recalling a saying of William James about certain passages of Hegel: that they were no doubt written with a passion of rationality; but that one cannot help wondering whether to the reader they have any significance save that the words are strung together with syntactical correctness.

Complexity is a separate issue from flatness of rate structures. In the United States, income tax codes are often legislatures' favored policy instrument for encouraging numerous undertakings deemed socially useful — including the buying of life insurance, the funding of employee health care and pensions, the raising of children, home ownership, development of alternative energy sources and increased investment in conventional energy. Special tax rebates granted for any purpose increase complexity, irrespective of the system's flatness or lack thereof.

State and territorial income taxes

Map of USA showing states with no state income tax in red, and states that tax only interest and dividend income in yellow.

Main article: State income tax

Income tax may also be levied by individual U.S. states and are on top of the federal income tax. In addition, some states allow individual cities to impose an additional income tax. However, state and local income taxes are deductible for federal tax purposes. Through this deduction, the federal government effectively subsidizes a portion of an individual's state income tax if the taxpayer itemizes deductions. Puerto Rico is treated as a separate taxing entity from the USA; its income tax rates are set independently, and residents do not pay federal income tax. Unincorporated Territories (Guam, American Samoa, and the Virgin Islands) all levy a mirror income tax at rates equal to the prevailing US federal tax; thus, to individual taxpayers these entities appear to be like the other states not having a local income tax.

Arguments against the U.S. income tax
For more details on this topic, see Tax protester arguments.
A libertarian viewpoint proposes the existence of a natural right to "enjoy all the fruits of one's own labor" (previously protected, some libertarians claim, by the Ninth Amendment). Taxation of income is argued to be an infringement on that right. Under this argument, income taxation offers the federal government a technique to radically diminish the power of the states, because the federal government is then able to distribute funding to states with conditions attached, often giving the states no choice but to submit to federal demands.


Proponents of a consumption tax argue that the income tax system creates perverse incentives by encouraging taxpayers to spend rather than save: a taxpayer is only taxed once on income spent immediately, while any interest earned on saved income is itself taxed. To the extent that this is considered unjust, it may be remedied in a variety of ways, e.g. excluding investment income from taxable income, making investments deductible and therefore only taxing them when gains are realized, or replacing the income tax by other forms of tax, such as a sales tax.The proposed Fair Tax Act, a bill before the U.S. Congress, repeals the income tax in favor of a national sales tax with a rebate, and calls for a repeal of the Sixteenth Amendment.


Some argue that the current income tax system, which is the government's largest revenue source, is too progressive and redistributive.In 2007, the top 5% of income earners paid over half of the federal income tax revenue.The top 1% of income earners paid 25% of the total income tax revenue. Forty percent of Americans pay no federal income tax,which raises moral concerns regarding wealth redistribution and the economics for controlling the size and spending of government.