How Far Back Can You Be Audited? 3, 6, or Forever?

For most taxpayers, the IRS has three years from the date you file to audit your return and assess additional tax. That window stretches to six years if you left off more than a quarter of your income, and it never closes at all if you filed a fraudulent return or didn’t file one. So the honest answer to how far back you can be audited is: usually three years, sometimes six, and in a handful of situations, forever.¹

Those windows are known as the Assessment Statute Expiration Date, or ASED. Which one applies to you depends on what’s on the return and whether you filed at all.

The Three-Year Default

Three years is the standard limit for the IRS to examine a return and bill you for any additional tax. The clock doesn’t start the moment you mail the return. It starts on the later of two dates: the day you actually file, or the original due date of the return.²

A few examples make the rule concrete. File your 2025 return on February 20, 2026, and the three years still run from April 15, 2026, because the due date is later. File late on July 10 with no extension, and the clock starts July 10. Request an extension to October 15 and file on September 3, and the three years run from September 3. Filing early never shortens the window. Filing late always pushes it out.¹

In practice, most individual returns never get looked at. The IRS examined roughly 0.3% of individual returns for tax year 2022. The three-year rule is less about predicting an audit and more about knowing when the risk of one meaningfully ends.

When the IRS Gets Six Years

Two situations double the standard window to six years, and both involve income that didn’t make it onto the return.

The first is a substantial omission of income. If you left off an amount greater than 25% of the gross income you did report, the six-year rule kicks in. The threshold is measured against what your return showed, not what it should have shown. A return reporting $100,000 in gross income when you actually earned $130,000 omits $30,000, which is 30% of the reported figure. That clears the 25% line, and the IRS now has six years instead of three.²

There’s a protective exception. If you disclosed the item on the return or in an attached statement clearly enough for the IRS to understand what it was, that amount doesn’t count toward the 25% test. Disclosure protects you even if the IRS later disagrees with how you treated the item.³

The second trigger involves foreign financial assets. If you failed to report more than $5,000 of income connected to assets that should have been disclosed on Form 8938, the six-year window applies on its own, with no need to meet the 25% threshold. For this test, the $5,000 figure covers all your specified foreign financial assets, including ones that fall below the normal Form 8938 reporting threshold.⁴

When There’s No Deadline at All

In a few serious scenarios, the audit window never closes. The IRS can come back and assess tax for the year in question years or even decades later.

Fraudulent returns. If you filed a false or fraudulent return with the intent to evade tax, there is no time limit on assessment. The IRS has to prove you acted willfully rather than carelessly, which is a high bar. When it clears that bar, the year stays open indefinitely.¹

No return filed. If you never filed for a particular year, the three-year clock never starts. The IRS can assess tax for that year at any point in the future. This is one reason that filing a late return is almost always better than filing none. A late return at least starts the clock.¹

Undisclosed gifts. Gift tax follows a similar rule. If you were required to file Form 709 and didn’t, or you filed one but failed to adequately disclose a gift, the IRS can assess gift tax on that transfer at any time. Adequate disclosure means supplying enough detail (a description of the property, the relationship between you and the recipient, and the method used to determine fair market value) for the IRS to evaluate the gift. Without that, the clock never starts.³

What Can Extend or Pause the Clock

Several less common situations change the standard timeline even when none of the rules above applies.

Signing a Consent to Extend

You and the IRS can mutually agree to extend the assessment deadline using Form 872, Consent to Extend the Time to Assess Tax. This usually comes up during a complex audit when the examiner needs more time to review records or you need more time to produce them. Signing is voluntary. The form itself tells you that you have the right to refuse or to limit the extension to specific issues or a specific time period.⁵

Receiving a Notice of Deficiency

When the IRS sends you a formal Notice of Deficiency (sometimes called a 90-day letter), the assessment clock pauses. The agency cannot assess the tax during the 90-day period you have to petition the Tax Court (150 days if you’re outside the United States), plus an additional 60 days after that period expires. If you do petition the Tax Court, the clock stays paused until the court reaches a final decision.

Skipping Form 8938

Failing to file Form 8938 does more than trigger the six-year rule for omitted foreign income. If you skip the form entirely when it was required, the statute of limitations for the whole return stays open until three years after you eventually file it. The return sits in limbo until you comply, and when the IRS does examine it, the review isn’t limited to the foreign asset items.⁴

Filing an Amended Return Near the Deadline

Filing an amended return doesn’t restart the three-year statute for the whole return. There’s one wrinkle: if the IRS receives your amended return within the final 60 days of the original assessment period and it shows additional tax owed, the IRS gets at least 60 days from the date of receipt to assess that extra amount. The rule only applies to amended returns showing more tax due. An amended return claiming a refund doesn’t extend the IRS’s window.²

Audit Deadlines Are Not Collection Deadlines

Worth knowing because it’s easy to confuse: the audit statute of limitations controls how long the IRS has to examine your return and determine what you owe. Once tax has been assessed, a separate 10-year clock starts for actually collecting the money. That Collection Statute Expiration Date (CSED) gives the IRS a decade from the assessment date to pursue payment through levies, liens, and other enforcement tools.⁶

So even after the three- or six-year audit window closes and the IRS can no longer increase what you owe for that year, the agency may still have years left to collect a balance that was already on the books.

How Long to Keep Your Records

Your record retention period should match the longest audit window that could realistically apply to you. The IRS guidance tracks the deadlines above:

Three years for most straightforward returns.
Six years if you might have underreported income by more than 25% of what your return showed.
Seven years if you claimed a loss from worthless securities or a bad debt deduction.
Indefinitely if you filed a fraudulent return or didn’t file at all.
At least four years for employment tax records, measured from the date the tax becomes due or is paid, whichever is later.

Property records need longer treatment. Keep anything related to real estate or other assets until the statute of limitations expires for the year you sell or dispose of the property, because the purchase price, improvement costs, and depreciation all affect the gain or loss you report at sale. For a home or rental property owned for decades, that can mean holding onto paperwork from the original purchase. If you received property in a tax-free exchange, keep records for both the old and new property until you eventually dispose of the new one.⁷

State Audits Follow Their Own Rules

Everything above governs federal returns only. Each state with an income tax sets its own audit statute of limitations, typically between three and six years for a standard return, with its own rules on fraud, extensions, and omitted income. Some states tie their audit window directly to the federal one, so a federal extension automatically extends the state’s as well. Check your state’s department of revenue for the specifics.

1
Internal Revenue Service. Time IRS Can Assess Tax
2
Office of the Law Revision Counsel. 26 USC 6501 – Limitations on Assessment and Collection
3
Office of the Law Revision Counsel. 26 USC 6501 – Limitations on Assessment and Collection
4
Internal Revenue Service. Instructions for Form 8938
5
Internal Revenue Service. Form 872 – Consent to Extend the Time to Assess Tax
6
Internal Revenue Service. Time IRS Can Collect Tax
7
Internal Revenue Service. How Long Should I Keep Records