How to file back taxes (unfiled tax returns)

If you skipped filing a tax return for one or more years, the answer is the same for every year: file it, even if you cannot pay. Get your income records (the IRS offers a free wage and income transcript), use the forms for that year, and send each return the way the IRS says. If you owe, you can then ask about a payment plan. If you are owed a refund, you generally have only three years from the return's due date to claim it.

Why file, even if you cannot pay

File all tax returns that are due, whether or not you can pay in full. Filing keeps your options open:

• You can claim a refund you are owed. To claim a refund of withholding or estimated tax, or a credit such as the Earned Income Credit, you must file the return within 3 years of its due date.
• You can use the IRS payment options. Online long-term payment plans and an offer in compromise both require that all required returns are filed.
• You protect your record. If you are self-employed and do not file, your self-employment income is not reported to the Social Security Administration, so you do not earn credits toward Social Security retirement or disability benefits. Loan approvals can also be delayed, because lenders ask for copies of filed returns.

What happens if you do not file

If you do not file, the IRS may file a substitute return for you, and it might not give you credit for deductions and exemptions you are entitled to.

The IRS then sends a Notice of Deficiency, CP3219N (a 90-day letter), proposing a tax assessment. You have 90 days to file your past due return or petition the Tax Court, and a CP3219N cannot be extended. Even then, filing your own return is in your best interest, and the IRS will generally adjust your account to the correct figures.

On a CP3219N, you have 90 days from the date shown on the notice to file a petition with the Tax Court, or 150 days if the notice is addressed to a person outside the country.

The tax bill from a substitute return, if unpaid, starts the collection process. That can include a levy on your wages or bank account or a notice of federal tax lien. See IRS wage garnishment and levies.

For a year you never filed, the IRS can assess tax at any time. The usual 3 year limit for assessing tax starts only when a return is filed.

How many years of unfiled returns do you need to file?

The IRS normally enforces filing of missing returns for up to the last six years, but it can ask for more or fewer years depending on the facts of your case.

This comes from the Internal Revenue Manual, the IRS's guidance for its own staff (section 4.12.1, which cites Policy Statement 5-133). Factors include a taxpayer's history of noncompliance. The manual says no manager approval is needed when a taxpayer voluntarily files returns for years beyond that period.

The six-year figure is guidance for IRS staff, not a promise that older years will be ignored. If the IRS wrote to you, answer for every year the letter names. IRS notice CP59 means the IRS has no record that you filed your prior year personal tax return. File your return right away, or explain why you do not need to file. If you are not sure which years apply to you, ask the IRS (see free help below) or a tax professional.

Step by step: how to file past due tax returns

1. List the years you did not file. Check your own records, then see what the IRS has on file. Your IRS online account shows balances owed by tax year and gives you access to transcripts and to information return documents such as Forms W-2 and certain 1099s. Go to the IRS online account page. A free tax account transcript shows basic data such as filing status and taxable income, plus changes made after you filed. It is generally available for the current and nine prior tax years in your IRS online account. If the IRS has written to you, the notice names the year.
2. Collect your income records. Ask your employers and payers for copies of your Forms W-2 and 1099. The IRS offers a free wage and income transcript, which shows data from information returns such as Forms W-2, 1098, 1099 and 5498, for the current and nine prior tax years. It shows only information returns that were filed with the IRS, which may not be everything issued to you. If you cannot get it in your IRS online account, you can request it with Form 4506-T. Written transcript requests made with Form 4506-T can take several weeks, so the IRS urges people to try the other options first. Use your own records too, because a transcript may not list everything.
3. Fill any gaps. If a Form W-2 or Form 1099-R is missing, contact your employer or payer first. If that does not work, the IRS can help at 800-829-1040 and may send you Form 4852, which lets you estimate your wages and withholding to complete your return.
4. Get the forms for each year. Use the Form 1040 and instructions for the year you are filing. Prior year forms and instructions are on IRS.gov, or you can order them by phone at 800-829-3676 (800-TAX-FORM). Go to the IRS prior year forms page.
5. Prepare each return. Fill in each year on its own return, with paper forms or software that supports that year. You can only file your current year return with IRS Free File. It cannot be used for a prior year (back taxes or past due) return. IRS e-file accepts Form 1040 returns for the current tax year and the two prior tax years. Since January 2026 it has accepted tax years 2025, 2024 and 2023. Older years are printed, signed and mailed.
6. File each return where the IRS says. File a past due return the same way and to the same location as an on-time return. If you received an IRS notice, send the return to the location on the notice. The IRS says it takes about 6 weeks to process an accurately completed past due return.
7. Pay what you can, and ask for time on the rest. If you cannot pay in full, a short-term payment plan gives you up to 180 days, with no setup fee; individuals who owe less than $100,000 in combined tax, penalties and interest may qualify to apply online. If you need longer, you can request a long-term payment plan (installment agreement). See IRS payment plans and the offer in compromise basics.

Penalties and interest on late returns

The IRS charges one penalty for filing late and another for paying late, plus interest.

• Late filing: The failure to file penalty is 5% of the tax due (less tax paid on time and available credits) for each month or part of a month the return is late, up to a maximum of 25%. The penalty does not apply if you can show the failure was due to reasonable cause.
• Late payment: The failure to pay penalty is 0.5% of the unpaid tax for each month or part of a month the tax stays unpaid, up to a maximum of 25%.

If both penalties apply in the same month, the failure to file penalty is reduced by the failure to pay penalty, so the two together are 5% for that month (4.5% plus 0.5%). The failure to file penalty reaches its maximum after 5 months, and the failure to pay penalty continues. The rate rises to 1% a month if you do not pay within 10 days of a notice of intent to levy. The IRS also charges interest on unpaid tax and on penalties until you pay in full.

Minimum penalty for a return more than 60 days late

If a Form 1040 is more than 60 days late, the minimum failure to file penalty is the amount below for the year the return was due, or 100% of the tax owed, whichever is less. A tax year 2024 return, for example, was due in 2025.

Can the penalties be reduced?

The IRS may remove penalties for filing or paying late. Automatic Exemption from Penalty (AEP) applies on its own to eligible returns beginning with tax year 2025 when you filed and paid on time in each of the prior three years. For earlier years, First Time Abate works the same way for people with that record, but you have to ask. If you do not qualify, you may request relief for reasonable cause. To ask, call the toll-free number on your notice or send a written statement or Form 843, Claim for Refund and Request for Abatement.

To qualify for AEP or First Time Abate you need a timely compliance history: the same type of return was filed on time for the prior three years (or 12 consecutive quarters), and either no penalty (other than the estimated tax penalty) was assessed or a penalty was assessed but later removed for reasonable cause or IRS error. If you are several years behind on returns, you may not have that record. See IRS penalty abatement: who qualifies and how to ask.

Refunds on old returns: the three-year limit

The latest date, by law, you can claim a credit or federal income tax refund for a tax year is generally the later of 3 years from the date you filed your return or 2 years from the date you paid the tax. If you file before the due date, the IRS treats the return as filed on the due date, and withholding and estimated tax payments count as paid on the due date. Your refund is limited to the amount you paid during the 3 years before you filed the claim, plus any extension of time you had to file.

The IRS announced the tax year 2022 deadline on March 20, 2026, and it has passed. Under the law, taxpayers usually have three years to file and claim a refund. If they do not file within three years, the money becomes the property of the U.S. Treasury. For tax year 2023, April 15, 2027 is our own calculation, not an IRS announcement. It is three years after the April 15, 2024 due date, under the same three-year rule the IRS cited for tax year 2022. The window can be longer in some cases, such as a federal disaster area, combat zone service, or a written agreement with the IRS to extend the time to assess tax.

A refund for an older year may be held if later years are also unfiled. Any refund is applied to amounts you still owe the IRS or a state tax agency, and may be used to offset unpaid child support or other past due federal debts, such as student loans.

Free help with back tax returns

• The IRS: For help filing a past due return, call the IRS at 800-829-1040 (TTY/TDD 800-829-4059).
• Volunteer tax sites: If you have difficulty preparing a past due return, you may be eligible for help from the Volunteer Income Tax Assistance (VITA) or Tax Counseling for the Elderly (TCE) programs. VITA generally serves people who make about $70,244 or less, and TCE focuses on people 60 or older. Ask the site whether it prepares prior year returns before you book. See VITA and TCE.
• Low Income Taxpayer Clinics: If the IRS has already contacted you about a prior year return and you need help preparing it, you may qualify for help from a Low Income Taxpayer Clinic. Clinics help for free or a small fee. Clinics generally serve people with income at or below 250% of the federal poverty guidelines (for 2026, $39,900 for a single person in the 48 contiguous states and D.C.; Alaska and Hawaii have higher figures). Each clinic decides whether you qualify. Clinics are independent of the IRS. Find a clinic.
• Taxpayer Advocate Service: an independent organization within the IRS that may be able to help with a tax problem you have not been able to resolve with the IRS, and its service is free if you qualify. Contact TAS.

When a tax professional makes sense

You may be able to handle one or two simple years yourself with the steps above. A tax professional (a CPA, enrolled agent, tax attorney or tax firm) can help if you have several years to file, were self-employed or have income without paperwork, the IRS has already filed a substitute return, you owe a large balance, or a notice mentions a levy or lien. Ask about the fee up front. Our guide to paid tax help explains how to choose.