Income tax is money the federal government and most states take from your paycheck or business earnings

Income tax is a percentage of the money you earn that goes to the federal government, and in most states, to your state government as well. The IRS (Internal Revenue Service) collects federal income tax. Your employer usually takes it out of each paycheck automatically — this is called withholding. If you're self-employed or earn money outside a regular job, you pay it yourself, usually four times a year.

The amount you owe depends on how much you earned and which tax bracket you fall into. The U.S. uses a progressive tax system, which means people who earn more money pay a higher percentage in taxes. The money collected funds federal programs like Social Security, Medicare, roads, defense, and schools.

You don't pay the same tax rate on every dollar you earn. Instead, your income is divided into brackets, and each bracket has its own rate. For example, in 2024, the first portion of your income might be taxed at 10%, the next portion at 12%, and so on. This is different from a flat tax, where everyone pays the same percentage regardless of income.

Key Takeaways

  • Income tax is a percentage of your earnings that goes to federal and state governments, collected by the IRS at the federal level.
  • Your employer usually withholds income tax from each paycheck, but self-employed people pay quarterly estimated taxes instead.
  • The amount you owe is based on your total income and which tax bracket you fall into — higher earners pay a higher percentage.
  • You file a tax return each year to report your actual income and either get a refund if too much was withheld or pay what you still owe.

How withholding works when you have a job

When you start a job, you fill out a Form W-4, which tells your employer how much federal income tax to take from each paycheck. Your employer sends that money to the IRS on your behalf throughout the year. The amount withheld depends on your filing status (single, married, head of household), how many dependents you have, and whether you have other income.

The goal of withholding is to have roughly the right amount taken out so that when you file your tax return at the end of the year, you either owe very little or get a small refund. If you withhold too much, you get money back. If you withhold too little, you owe the IRS when you file. You can adjust your W-4 at any time during the year if your situation changes — for example, if you get married, have a child, or take a second job.

Self-employment and quarterly taxes

If you're self-employed, run a business, or earn significant income outside a regular job (like freelance work or rental income), you don't have an employer to withhold taxes for you. Instead, you're responsible for paying estimated taxes four times a year using Form 1040-ES. These payments are due in April, June, September, and January.

To calculate your estimated tax, you figure out what you expect to earn for the year, subtract deductions you're allowed to take, and then calculate what you owe based on the tax brackets. If you don't pay enough throughout the year, you'll owe the difference when you file your return, plus a penalty. If you overpay, you get a refund or can explore it to next year's taxes.

Tax brackets and how they actually work

A tax bracket is a range of income taxed at a specific rate. The brackets change each year and are different depending on your filing status. For 2024, a single person might pay 10% on income up to about $11,600, then 12% on income from $11,601 to about $47,150, and so on. The rates go up to 37% for the highest earners.

A common mistake is thinking that if you move into a higher tax bracket, all your income gets taxed at that higher rate. That's not how it works. Only the income within each bracket is taxed at that bracket's rate. So if you earn $50,000 as a single person in 2024, you don't pay 22% on all $50,000. You pay 10% on the first portion, 12% on the next portion, and 22% only on the portion that falls in the 22% bracket.

Filing your tax return and getting a refund or paying what you owe

Every year by April 15, you file a tax return with the IRS (and your state, if your state has income tax). On this return, you report all the income you earned during the previous year from all sources — wages, self-employment, investments, rental property, and anything else. You also claim deductions and credits that reduce the amount of tax you owe.

After you file, the IRS compares what you actually earned to what was already withheld or paid through estimated taxes. If more was withheld than you owe, you get a refund. If less was withheld, you pay the difference. You can file on your own using tax software, hire a tax professional, or use the IRS Free File program if your income is below a certain threshold.

State income tax

Most states also collect income tax, though the rates and rules vary widely. Some states have no income tax at all — currently Alaska, Florida, Nevada, South Dakota, Tennessee, Texas, Washington, and Wyoming don't tax income. Other states have rates ranging from about 1% to over 13%, depending on your income level.

If you live in a state with income tax, your employer withholds state tax from your paycheck just like federal tax, and you report it on your state tax return. If you work in one state but live in another, you may have to file returns in both states, though you usually get a credit to avoid paying tax twice on the same income. Some states also have local income taxes on top of state tax.

Deductions and credits that reduce what you owe

A deduction is an amount of income you don't have to pay tax on. The standard deduction is a flat amount that most people can subtract from their income — in 2024, it's about $13,850 for single filers and $27,700 for married couples filing jointly. If you own a home, pay student loan interest, or have significant medical expenses, you might be able to itemize deductions instead, which means listing out specific expenses that reduce your taxable income.

A tax credit is different from a deduction — it directly reduces the amount of tax you owe, dollar for dollar. For example, the Earned Income Tax Credit (EITC) is a credit for people with lower incomes. The Child Tax Credit gives you money back for each dependent child. Credits are usually more valuable than deductions because they reduce your actual tax bill rather than just the income that gets taxed.

Frequently Asked Questions

Why does the government take income tax from my paycheck?

The federal government uses income tax to fund programs like Social Security, Medicare, national defense, infrastructure, and education. States use state income tax for schools, roads, and state programs. The amount you pay is based on your income level.

Can I change how much income tax is withheld from my paycheck?

Yes. Fill out a new Form W-4 and give it to your employer's payroll department. You can increase or decrease your withholding based on your situation — for example, if you got married, had a child, or took a second job. Changes usually take effect on your next paycheck.

What happens if I don't file a tax return?

If you owe taxes and don't file, the IRS will eventually contact you and charge penalties and interest on the amount owed. If you're due a refund, you won't get it unless you file. You generally have three years to claim a refund before it's forfeited.

Is there a difference between income tax and payroll tax?

Yes. Income tax funds general government operations. Payroll tax (Social Security and Medicare tax) is separate and funds those specific programs. Both are withheld from your paycheck, but they're calculated and used differently.

Do I have to pay income tax on all money I receive?

Most income is taxable, but some isn't — for example, gifts, inheritances, and certain types of financial aid. Interest from municipal bonds is usually not taxable. Your tax return instructions and the IRS website explain which types of income are taxable and which aren't.