What Is Income Tax and How Are Different Types Calculated?

What Is Income Tax?

The term “income tax” refers to a type of tax governments impose on income businesses and individuals within their jurisdiction generate. By law, taxpayers must file an income tax return annually to determine their tax obligations.

Income taxes are a source of revenue for governments. They are used to fund public services, pay government obligations, and provide goods for citizens. In addition to the federal government, many states and local jurisdictions also levy income taxes.

Certain investments, like housing authority bonds, are exempt from income taxes in some cases.

How Income Tax Works

The Internal Revenue Service (IRS) collects taxes and enforces tax law in the United States. The IRS employs a complex set of rules and regulations regarding reportable and taxable income, deductions, credits, etc. The agency collects taxes on all forms of income, such as wages, salaries, commissions, investments, and business earnings.

The personal income tax that the government collects can help fund government programs and services, such as Social Security, national security, schools, and roads.

History of Income Tax

The United States imposed the nation’s first income tax in 1862 to help finance the Civil War. After the war, the tax was repealed, but it was reinstated after passage of the Revenue Act of 1913. That same year, Form 1040 was introduced.

Most countries, including the U.S., employ a progressive income tax system in which higher-income earners pay a higher tax rate compared with their lower-income counterparts. The idea behind progressive tax is that those who earn high incomes can afford to pay more tax. For 2023 and 2024, federal income tax rates range from 10% to 37%.

Types of Income Tax

Individual Income Tax

Individual income tax is also referred to as personal income tax. This type of income tax is levied on an individual’s wages, salaries, and other types of income. This tax is usually a tax that the state imposes. Because of exemptions, deductions, and credits, most individuals do not pay taxes on all of their income.

The IRS offers a series of income tax deductions and tax credits taxpayers can use to reduce their taxable income. While a deduction can lower your taxable income and the tax rate used to calculate your tax, a tax credit reduces your income tax obligation.

The IRS offers tax deductions for healthcare expenses, investments, and certain education expenses. For example, if a taxpayer earns $100,000 in income and qualifies for $20,000 in deductions, the taxable income reduces to $80,000 ($100,000 - $20,000 = $80,000).

Tax credits help reduce the taxpayer’s tax obligation or amount owed. They were created primarily for middle-income and lower-income households. To illustrate, if an individual owes $20,000 in taxes but qualifies for $4,500 in credits, their tax obligation reduces to $15,500 ($20,000 - $4,500 = $15,500).

Business Income Tax

Businesses also pay income taxes on their earnings; the IRS taxes income from corporations, partnerships, self-employed contractors, and small businesses. Depending on the business structure, the corporation, its owners, or shareholders report their business income and then deduct their operating and capital expenses. Generally, the difference between their business income and their operating and capital expenses is considered their taxable business income.

State and Local Income Tax

Most U.S. states also levy personal income taxes. But eight states don’t impose personal income taxes on residents: Alaska, Florida, Nevada, South Dakota, Tennessee, Texas, Washington, and Wyoming. Tennessee repealed its Hall tax, which taxed dividends and interest, on Jan. 1, 2021.

New Hampshire also has no state tax on income, but residents must pay a 5% tax on any dividends and interest that they earn. The state passed a bill in 2018 that would phase out the state 5% tax on interest and dividends on Jan. 1, 2024. This will bring the number of states with no income tax to nine by 2024.

Keep in mind, though, that it may not necessarily be cheaper to live in a state that does not levy income taxes. This is because states often make up the lost revenue with other taxes or reduced services. What's more, other factors determine the affordability of living in a state, including healthcare, cost of living, and job opportunities. For instance, Florida residents pay a 6% sales tax on goods and services, while the state sales tax in Tennessee is 7%.

To further complicate matters, states continually adjust their tax systems in ways both large and small, making it impossible to predict what sort of tax burden their residents will face in the years to come.

The Bottom Line

All taxpayers pay federal income tax. Depending on where you live, you may have to pay state and local income taxes, too. The U.S. has a progressive income tax system, which means that higher-income earners pay a higher tax rate than those with lower incomes. Most taxpayers do not pay taxes on all of their income, thanks to exemptions and deductions.