What a tax return is and why you file one

A tax return is a form you send to the IRS (Internal Revenue Service) that reports how much money you earned in a year and how much tax you already paid on it. The IRS uses your return to figure out whether you owe more tax, are owed a refund, or are even. You file a return because federal law requires most people who earned income above a certain threshold to do so — even if no tax was taken out of your paychecks.

The return itself is not a request for money or a bill. It is a record. You are telling the IRS: here is what I earned, here is what was withheld, here are the deductions and credits I am claiming. The IRS then processes that information and either sends you a refund, bills you for more tax, or confirms you are square.

Most people file once per year, usually between January and April 15th. Self-employed people, people with investment income, and people with complex situations may need to file quarterly estimated tax payments instead of or in addition to an annual return.

Key Takeaways

  • A tax return reports your income for the year and tells the IRS how much tax you already paid through withholding or estimated payments.
  • The IRS uses your return to calculate whether you owe additional tax, are owed a refund, or have paid the correct amount.
  • You must file if your income exceeds a threshold that changes each year based on your age, filing status, and type of income.
  • Most people file once per year by April 15th using either Form 1040 (the main form) plus schedules, or a simplified form if your situation is straightforward.
  • If you do not file when required, the IRS can assess penalties and interest, and you may lose the right to claim a refund after three years.

Who has to file a tax return

You must file a federal tax return if your income is above a certain amount. That threshold depends on your age, your filing status (single, married filing jointly, head of household, etc.), and the type of income you earned. For 2024, a single person under 65 with only wage income must file if they earned more than $14,600. A married couple filing jointly, both under 65, must file if their combined income exceeded $29,200. These numbers change each year.

The threshold is higher if you are 65 or older. It is also different if you are self-employed — you must file if your net self-employment income was $400 or more, regardless of your other income. If you had income from investments, rental property, or other sources, the rules are different again.

Even if your income is below the threshold, you should file if you had tax withheld from your paychecks or made estimated tax payments. You will not get a refund unless you file a return showing what was withheld.

The main form and what goes on it

Form 1040 is the standard federal income tax return. It is a two-page form that asks for your name, address, Social Security number, filing status, and income from all sources. Most people use Form 1040 plus additional schedules (separate forms that attach to the 1040) depending on their situation.

The 1040 itself has lines for wages, interest, dividends, capital gains, and other common types of income. If you have self-employment income, rental income, or farm income, you fill out a separate schedule and report the total on the 1040. If you are claiming deductions or credits, you list those on the 1040 or on a schedule that attaches to it.

At the bottom of the 1040, you calculate your total tax owed for the year. You then subtract any tax that was already withheld from your paychecks (shown on your W-2 form) or any estimated tax payments you made. The difference is either a refund owed to you or additional tax you owe to the IRS.

Deductions and credits: the difference and how they work

A deduction reduces the amount of income the IRS counts as taxable. If you earned $60,000 and claim $10,000 in deductions, the IRS taxes you on $50,000 instead. Deductions include mortgage interest, property taxes, charitable donations, and medical expenses above a certain threshold. You can either itemize deductions (list them individually on Schedule A) or take the standard deduction, a flat amount set by the IRS each year. For 2024, the standard deduction is $14,600 for a single person and $29,200 for married couples filing jointly. Most people take the standard deduction because it is simpler and often larger than their itemized deductions would be.

A credit is different — it reduces your tax dollar-for-dollar. If you owe $3,000 in tax and claim a $1,000 credit, you owe $2,000. Credits are usually worth more than deductions because they directly cut your tax bill. Common credits include the Earned Income Tax Credit (EITC), the Child Tax Credit, and the American Opportunity Tax Credit for education expenses.

Some credits are refundable, meaning if the credit is larger than the tax you owe, the IRS sends you the difference as a refund. The EITC and the Additional Child Tax Credit are refundable. Other credits are non-refundable — they can reduce your tax to zero but not below.

How withholding and estimated payments work

When you work for an employer, your employer withholds federal income tax from each paycheck based on information you provide on a Form W-4. You fill out the W-4 when you start a job, and you can change it anytime. The more allowances or dependents you claim on the W-4, the less tax is withheld. The goal is to have roughly the right amount withheld so that when you file your return, you either owe very little or are owed a small refund.

If you are self-employed or have income that is not subject to withholding (like investment income or rental income), you may need to make estimated tax payments four times per year: April 15th, June 15th, September 15th, and January 15th of the following year. You calculate how much tax you expect to owe for the year and pay one-quarter of it each quarter. If you do not make estimated payments and end up owing a large amount when you file, the IRS charges you a penalty.

When you file your return, you report all the tax that was withheld (from your W-2 forms) or all the estimated payments you made. The IRS subtracts that from your total tax liability. If more was withheld or paid than you owe, you get a refund. If less was withheld or paid, you owe the difference.

Filing status and how it affects your taxes

Your filing status determines your tax rate, your standard deduction amount, and which credits you can claim. The five filing statuses are: single, married filing jointly, married filing separately, head of household, and may have access to widow(er).

Single is for unmarried people. Married filing jointly is for married couples and usually results in the lowest tax. Married filing separately is rarely used because it usually results in higher tax, but it may be necessary if spouses have very different income levels or if one spouse is disputing the return. Head of household is for unmarried people who pay more than half the household expenses and have a may have access to dependent living with them — it has a lower tax rate than single status. may have access to widow(er) is available for two years after a spouse dies if you have a dependent child and meet other conditions.

Your filing status is determined on December 31st of the tax year. If you get married on December 31st, you can file as married for that entire year. If you divorce on January 1st, you file as single for the previous year.

What happens after you file

After you file your return, the IRS processes it. This usually takes 21 days if you file electronically and claim a refund. If you file on paper, it takes longer — typically 4 to 6 weeks. The IRS will send you a notice confirming that your return was received and processed. If you are owed a refund, the IRS deposits it into your bank account (if you provided banking information) or mails you a check.

If you owe tax, the IRS will send you a bill with a due date. You can pay online, by phone, by mail, or through an installment agreement if you cannot pay in full. If you do not pay by the due date, the IRS charges interest and penalties.

The IRS may also audit your return, meaning they ask you to provide documents to support the income, deductions, or credits you claimed. Audits are uncommon — the IRS audits fewer than 1% of returns — but if you are selected, you will receive a notice in the mail explaining what documents to send.

Frequently Asked Questions

What if I miss the April 15th deadline?

You can file late, but the IRS charges a penalty if you owe tax. The penalty is usually 5% of the unpaid tax per month, up to 25%. If you are owed a refund, there is no penalty for filing late, but you lose the right to claim that refund after three years. You can request an extension to file by October 15th, but an extension to file is not an extension to pay — if you owe tax, you still owe it by April 15th or you will be charged interest and penalties.

Do I need to keep receipts and documents when I file?

You do not send receipts with your return, but you must keep them for your records. The IRS can ask you to provide documentation for any income, deduction, or credit you claimed, usually for up to three years after you file (six years if you underreported income by 25% or more). Keep W-2s, 1099s, mortgage statements, charitable donation receipts, medical bills, and anything else that supports what you reported.

What is the difference between a refund and a tax credit?

A refund is money the IRS sends you because you overpaid your tax during the year — more was withheld or paid in estimated taxes than you actually owed. A tax credit is a reduction in the tax you owe. Some credits are refundable, meaning if the credit exceeds your tax, you get the difference as a refund. Others are non-refundable and can only reduce your tax to zero.

Can I file my return myself or do I need a tax professional?

You can file yourself if your situation is straightforward — you have only wage income, take the standard deduction, and claim no credits. Many people use free tax software provided by the IRS or by private companies. If you are self-employed, have investment income, own rental property, or claim multiple credits, working with a tax professional (a CPA or enrolled agent) may save you money by finding deductions or credits you missed.

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

You can set up a payment plan with the IRS. A short-term plan lets you pay within 120 days with no setup fee. A long-term installment agreement lets you pay over months or years and requires a setup fee (usually $31 to $225 depending on how you pay). You can request a plan online, by phone, or by mail. Interest and penalties continue to accrue until the debt is paid in full.