Federal tax is money withheld from your paycheck or paid directly to the U.S. government based on how much you earn

When you work, your employer takes a portion of each paycheck and sends it to the Internal Revenue Service (IRS). This is federal income tax. The amount withheld depends on your income level, filing status (single, married, head of household), and the number of dependents you claim. If you're self-employed, you pay federal tax directly to the IRS, usually in quarterly installments.

Federal tax funds national programs: Social Security, Medicare, defense, infrastructure, and federal agencies. It's separate from state income tax (which some states don't have) and local taxes. Every year, you file a tax return to reconcile what was withheld against what you actually owe. If too much was taken, you get a refund. If too little was taken, you owe the difference.

Key Takeaways

  • Federal tax is withheld from paychecks by employers or paid quarterly by self-employed people, based on income and the W-4 form you complete.
  • The amount you owe depends on your tax bracket, which is determined by your total income for the year, not your paycheck amount.
  • You file a tax return each year (usually by April 15) to report your income and either receive a refund or pay what you still owe.
  • Federal tax funds national programs like Social Security, Medicare, and defense, and is separate from state and local taxes.
  • If you earn below a certain threshold, you may not owe federal tax at all, though filing a return can still get you money back through credits.

How much federal tax comes out of your paycheck

Your employer calculates federal tax withholding using information from your W-4 form, which you complete when you're hired. The W-4 asks for your filing status, number of dependents, and any additional income or deductions. The more dependents you claim or the more you adjust the form, the less is withheld. The fewer you claim, the more is withheld.

The IRS publishes tax tables and withholding formulas each year. Your employer uses these to calculate the federal amount from each paycheck. This is not the same as your tax bracket. Your bracket determines your final tax bill; withholding is an estimate taken throughout the year. You can adjust your W-4 at any time if you want more or less withheld—for example, if you got married, had a child, or took a second job.

Your pay stub shows the federal tax withheld as "FIT" or "Federal Income Tax." It also shows Social Security tax (6.2% of wages) and Medicare tax (1.45% of wages), which are separate from federal income tax, though they're often confused with it.

Tax brackets and how they determine what you owe

The U.S. uses a progressive tax system, meaning tax rates increase as income increases. The government divides income into brackets, and each bracket has a different rate. For example, in 2024, a single filer might pay 10% on the first portion of income, 12% on the next portion, and so on. You do not pay the highest rate on all your income—only on the portion that falls in that bracket.

Tax brackets change every year and depend on your filing status. A married couple filing jointly has higher brackets than a single filer with the same income. The IRS announces new brackets each January. Your total federal tax bill is calculated by adding up the tax owed on each bracket of your income, then subtracting any credits you're may have access to to (such as the Earned Income Tax Credit if you have low income).

Your employer's withholding is an estimate based on your W-4. It may not exactly match what you owe. If you had a major life change—marriage, divorce, job loss, or a large bonus—your withholding may be too high or too low, and you'll either owe money or receive a refund when you file your return.

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

Each year, you file a tax return with the IRS, usually by April 15. The return reports all income you earned in the previous year—wages, self-employment income, interest, dividends, rental income, and other sources. You also report deductions and credits that reduce your tax bill.

Most people use tax software (some free through the IRS Free File program) or hire a tax preparer. You'll need documents from your employer (a W-2 form if you're an employee, or 1099 forms if you're self-employed or received other income). The return calculates your total tax owed, subtracts what was already withheld, and shows either a refund or an amount due.

If you're owed a refund, the IRS typically sends it within 21 days of processing your return, though it can take longer if there are errors or if you claim certain credits. If you owe money, you can pay in full by the deadline or set up a payment plan with the IRS. Failure to file or pay on time results in penalties and interest.

Who has to file a federal tax return

You must file a federal return if your income exceeds a threshold set by the IRS each year. The threshold depends on your age, filing status, and type of income. For 2024, a single person under 65 with only wage income must file if they earned more than roughly $14,000 (this amount changes yearly). If you're self-employed, the threshold is lower—around $400 in net self-employment income.

Even if you don't meet the filing requirement, you should file if you had federal tax withheld from your paychecks or if you're may have access to to refundable credits like the Earned Income Tax Credit or Child Tax Credit. These credits can result in a refund even if you owe no tax. If you received unemployment benefits, you may also want to file to claim credits that reduce the tax on that income.

Deductions and credits that lower your federal tax bill

Federal tax law allows you to reduce your taxable income through deductions or reduce your tax bill directly through credits. A deduction lowers the income amount that's taxed; a credit directly reduces the tax you owe, dollar for dollar.

Most people use the standard deduction, a flat amount set by the IRS each year that you subtract from your income. For 2024, the standard deduction is roughly $14,600 for a single filer and $29,200 for a married couple filing jointly (these amounts increase yearly and are higher if you're over 65). If your deductible expenses (mortgage interest, property taxes, charitable donations) exceed the standard deduction, you can itemize instead, but most people benefit from the standard deduction.

Common credits include the Earned Income Tax Credit (for low to moderate income workers), the Child Tax Credit (for each dependent child), and the Child and Dependent Care Credit (if you paid for childcare). Credits are more valuable than deductions because they reduce your tax dollar-for-dollar. Some credits are refundable, meaning you can receive more than you owe in tax.

Self-employment and federal tax

If you're self-employed, you pay federal income tax plus self-employment tax (Social Security and Medicare). You don't have an employer withholding, so you must pay estimated tax quarterly—on April 15, June 15, September 15, and January 15. Each payment covers roughly one-quarter of your expected annual tax bill.

To calculate estimated payments, you project your net income for the year (revenue minus business expenses), apply the tax rate, and divide by four. If you underpay, you'll owe interest and penalties when you file your return. If you overpay, you'll receive a refund. Many self-employed people work with a tax preparer or accountant to get the quarterly amounts right.

Self-employed people can also deduct business expenses—office supplies, equipment, vehicle mileage, home office costs, and other ordinary business costs—which reduces taxable income. You report these on Schedule C when you file your return.

Frequently Asked Questions

What's the difference between federal tax and FICA taxes?

Federal income tax and FICA (Social Security and Medicare) are two separate taxes. Federal income tax funds general government operations. FICA taxes fund Social Security and Medicare specifically. Both are withheld from paychecks, but they're calculated and used differently. Your pay stub shows them as separate line items.

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

Yes. Complete a new W-4 form and give it to your employer's payroll department. You can claim more dependents to reduce withholding or fewer to increase it. You can also request an additional flat amount be withheld each pay period. Changes take effect on the next paycheck or within a few pay periods.

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

If you owe tax and don't file, the IRS can assess penalties and interest, and the debt doesn't go away. If you're owed a refund, you have three years to claim it before it's forfeited. If you received certain income (like 1099 income), the IRS may already know about it and will contact you if you don't file.

Do I have to pay federal tax if I'm retired?

It depends on your income. If your only income is Social Security, you typically don't owe federal tax (though some is withheld if you request it). If you have other income—pensions, retirement account withdrawals, investment income—you may owe tax. The threshold for filing is the same as for working people, adjusted for age.

What's the difference between a tax refund and a tax credit?

A refund is money the IRS returns to you because too much was withheld or because you overpaid. A credit is a reduction in your tax bill. A refundable credit can result in a refund if it's larger than your tax bill. A non-refundable credit can only reduce your tax to zero.