Income tax is a tax on the money you earn from work, investments, and other sources

Income tax is money the federal government and most states take from your paycheck or require you to pay based on what you earned during the year. It is different from sales tax (which you pay when you buy something) or property tax (which you pay on real estate). Income tax is calculated as a percentage of your total earnings, and the percentage goes up as you earn more — this is called a progressive tax system.

The federal government collects income tax through the Internal Revenue Service (IRS). Most states also collect their own income tax, though a few states do not. When you work for an employer, they usually take income tax out of each paycheck automatically. If you are self-employed or have income from investments, you typically pay the IRS directly, usually four times a year in what are called estimated tax payments.

Key Takeaways

  • Income tax is a percentage of your earnings that goes to the federal government and most state governments.
  • The percentage you pay increases as your income increases — earning more money puts you in a higher tax bracket.
  • Your employer usually removes income tax from your paycheck before you receive it, or you pay it directly to the IRS if you are self-employed.
  • You file a tax return once a year to report all your income and either get money back (a refund) or pay what you still owe.
  • Deductions and credits can lower the amount of income tax you owe by reducing your taxable income or the tax itself.

How tax brackets work and why earning more does not mean paying more tax

The federal government uses tax brackets to determine how much income tax you owe. A tax bracket is a range of income amounts, each with its own tax rate. For example, in 2024, the first portion of your income (roughly up to $11,600 if you are single) is taxed at 10 percent, the next portion (up to about $47,150) is taxed at 12 percent, and so on. The rates go higher as the income amounts get larger.

A common mistake is thinking that moving into a higher tax bracket means all your income gets taxed at that higher rate. That is not how it works. Only the income that falls into each bracket is taxed at that bracket's rate. If you earn $50,000 as a single person, you do not pay 22 percent on all of it — you pay 10 percent on the first $11,600, 12 percent on the next portion, and 22 percent only on the amount above $47,150. This means earning more money always results in taking home more money, even though your tax rate goes up.

What counts as income for tax purposes

Income is not just your paycheck. The IRS counts many types of earnings as income that you must report on your tax return. Wages and salaries from your job are the most common, but you also report income from self-employment (if you run a business or freelance), interest from savings accounts or bonds, dividends from stocks, rental income from property you own, and capital gains (profit from selling an investment or asset for more than you paid for it).

Some types of money are not counted as income. For example, gifts, inheritances, and money you borrow do not count as income because you are not earning them — you are receiving them as transfers. Certain benefits like Social Security (in some cases) and workers' compensation may be partially or fully excluded from income. The IRS publishes detailed rules about what counts, and your tax return form will ask you to report different types of income in different places.

Deductions and credits that reduce what you owe

The government offers ways to reduce your income tax through deductions and credits. A deduction lowers the amount of your income that is subject to tax — if you earn $50,000 and have $10,000 in deductions, you only pay tax on $40,000. A credit directly reduces the tax you owe dollar for dollar — a $1,000 credit means you pay $1,000 less in tax.

The most common deduction is the standard deduction, which is a fixed amount the IRS lets you subtract from your income with no questions asked. For 2024, the standard deduction is roughly $13,850 for single filers and $27,700 for married couples filing jointly (these amounts change each year). You can also itemize deductions instead — listing specific expenses like mortgage interest, state and local taxes, or charitable donations — but only if your itemized total is higher than the standard deduction.

Credits are often more valuable because they reduce your tax dollar for dollar. Common credits include the Earned Income Tax Credit (EITC) for lower-income workers, the Child Tax Credit for parents, and the American Opportunity Credit for students paying for college. You report credits on your tax return, and they lower your final tax bill.

When you file your tax return and what happens if you do not

You file your federal income tax return once per year, usually by April 15. You report all the income you earned during the previous calendar year (January through December), claim any deductions or credits you are may have access to to, and calculate how much tax you owe or how much you should get back as a refund. Most people file electronically using tax software or a tax preparer, though you can also file by mail.

If you do not file a tax return when you are required to, the IRS can assess penalties and interest on any tax you owe. If you are owed a refund but do not file, you straightforward do not receive it — the government keeps the money. If you cannot file by the important date, you can request an extension, which gives you until October 15 to file without penalty (though any tax you owe is still due by April 15).

The difference between your gross pay and your take-home pay

Your gross pay is the total amount your employer pays you before anything is taken out. Your take-home pay (or net pay) is what you actually receive after income tax, Social Security tax, Medicare tax, and any other deductions are removed. Income tax is usually the largest deduction on your paycheck, but it is not the only one.

Your employer calculates how much income tax to withhold from each paycheck based on a form you fill out called a W-4. The W-4 asks about your filing status, number of dependents, and other income sources so the employer can estimate your annual tax and spread it across your paychecks. If your employer withholds too much, you get a refund when you file your return. If they withhold too little, you owe money when you file.

State income tax and how it differs from federal income tax

Most states collect their own income tax in addition to the federal income tax you pay. State income tax rates vary widely — some states have no income tax at all (including Alaska, Florida, Nevada, South Dakota, Tennessee, Texas, Washington, and Wyoming), while others have rates ranging from about 1 percent to over 13 percent. A few states tax only certain types of income, like dividends and capital gains.

You file a separate state tax return (or sometimes the same return serves both purposes) and report your income to your state. Your employer usually withholds state income tax from your paycheck as well, based on a state W-4 form. The rules for deductions, credits, and what counts as income can differ between your state and the federal government, so you may owe a different amount to each.

Frequently Asked Questions

Why do I get a tax refund if my employer already took money out of my paycheck?

Your employer estimates how much tax you will owe for the year and withholds that amount spread across your paychecks. If they withhold more than you actually owe (because you have deductions, credits, or life changes they did not know about), you get the overpayment back as a refund when you file your return.

Do I have to file a tax return if I did not earn much money?

It depends on how much you earned. For 2024, you generally do not have to file if your income is below the standard deduction for your filing status (roughly $13,850 for single filers). However, if your employer withheld income tax from your paycheck, you should file to get that money back as a refund.

What happens if I owe income tax but cannot pay it all at once?

The IRS offers payment plans that let you pay your tax bill in installments over time. You can set up a short-term plan (up to 180 days) or a long-term installment agreement. Interest and penalties will continue to accrue on the unpaid balance, but a payment plan prevents additional enforcement action.

Can I reduce my income tax by contributing to a retirement account?

Yes. Contributions to traditional 401(k)s and traditional IRAs reduce your taxable income, lowering your income tax bill. Contributions to Roth accounts do not reduce your current tax but grow tax-free. Your employer or financial institution can explain which type of account fits your situation.

Is income tax the same as payroll tax?

No. Income tax and payroll tax are separate. Payroll tax includes Social Security tax and Medicare tax, which are taken from your paycheck for those specific programs. Income tax is separate and goes to the general treasury. Your paycheck shows all three deducted.