IRS Audit Statue Of Limitations: How Long Does The IRS Have To Come After You?

The IRS generally has 3 years from the date you file to audit your tax return. That window stretches to 6 years if you leave off more than 25% of your gross income, and there is no time limit at all if you never file a return or file a fraudulent one. Idaho has its own 3-year audit window for state tax returns, with a similar set of exceptions. Knowing which clock applies to your situation tells you exactly how long to keep your records and when you are actually in the clear.

If you have ever wondered whether an old tax return could still come back to bite you, you are not alone. The IRS audit statute of limitations is one of the most misunderstood parts of the tax code, partly because there is not just 1 rule. There are 3, and which 1 applies to you depends on what was on your return (or whether you filed one at all).

The 3-Year Rule: How Long The IRS Usually Has To Audit You

For the vast majority of taxpayers, the IRS has 3 years from the date you file your return, or the due date of the return, whichever is later, to open an audit and assess additional tax. The IRS calls this the Assessment Statute Expiration Date, or ASED.

• If you filed your 2022 return on the April deadline, the IRS generally has until that same date in 2026 to audit it.
• If you filed late with no extension, the 3-year clock starts on the date you actually filed, not the original due date.
• If you got an extension and filed by the extended deadline, the clock still starts from the due date, not your early or on-time filing date within the extension window.

Once that 3-year window closes, the IRS generally cannot open a new audit or assess more tax on that return. This is why keeping 3 years of tax records is the baseline every CPA recommends, though there are good reasons to hold onto some documents longer, covered below.

When The IRS Gets 6 Years Instead Of 3

The 3-year rule doubles to 6 years if you omit more than 25% of your gross income from a return. This does not have to be intentional. If you earned $200,000 and only reported $140,000, for example, that 30% gap is enough to trigger the extended window even if the omission was a genuine mistake.

The 6-year rule also applies if you failed to report more than $5,000 in gross income from foreign financial assets, such as interest from an overseas bank account. This lines up with the reporting period for FBAR (foreign bank account report) filings, which carry their own steep penalties for noncompliance.

Note that overstating deductions or credits, as opposed to omitting income, does not trigger the 6-year rule. That distinction has actually been tested in court, and the extended statute only applies to unreported income, not inflated write-offs.

When There Is No Time Limit At All

In 3 specific situations, the statute of limitations never starts running, which means the IRS can audit you at any time, with no expiration date:

1. You never filed a return. No filing means no clock. The IRS can assess tax on unfiled years indefinitely.
2. You filed a false or fraudulent return with intent to evade tax. Fraud removes the time limit entirely.
3. You did not sign your return. An unsigned return is not considered valid by the IRS, so the 3-year period never begins.

If the IRS never received a valid, signed return for a given year, that year effectively stays open forever. This is one of the clearest reasons to always file, even if you cannot pay what you owe. An imperfect return that starts the clock is almost always better than no return at all.

What Actually Starts The Clock

A lot of confusion around this topic comes down to 1 question: which date counts as day 1? The rule is the later of 2 dates: the original due date of the return, or the date you actually filed it.

• File on time (or early): the clock starts on the due date.
• File with an approved extension, by the extended deadline: the clock starts on the original due date, not the extended one.
• File late with no extension: the clock starts on the date you actually filed.

This matters most for people who file late. A return filed 2 years after the deadline does not give the IRS 5 years of runway (3 plus the 2-year delay); it gives them 3 years from the actual, late filing date.

Can The Statute Of Limitations Be Extended?

Yes, but only with your agreement. If an audit is underway and the IRS needs more time to finish reviewing your return before the statute expires, an auditor may ask you to sign Form 872, Consent to Extend the Time to Assess Tax. You are allowed to negotiate the length of the extension, limit it to specific issues, or decline to sign altogether. Refusing does not stop the audit, but it does force the IRS to work within whatever time remains on the original 3-year clock, which sometimes prompts a faster resolution.

This is exactly the kind of decision where having a CPA in your corner during the audit, rather than navigating it alone, makes a real difference. Our IRS representation services exist for exactly this situation, and our tax planning team can also help you get ahead of issues before they trigger a longer look-back period in the first place.

Idaho's Audit Statute Of Limitations: What Is Different At The State Level

Most articles on this topic stop at the federal rules and never mention that Idaho runs its own, separate clock. For Idaho Falls taxpayers and business owners, both timelines matter.

• Idaho income tax: The Idaho State Tax Commission generally has 3 years from the later of the filing date or due date to issue a notice of deficiency, mirroring the federal rule.
• Federal audit adjustments reopen the Idaho clock: Under Idaho Code 63-3068(f), if a federal audit changes your taxable income, Idaho's period to assess additional state tax reopens and does not expire until 1 year after you report that federal change to the state, or 3 years from your original filing date, whichever is later. In other words, an IRS audit can indirectly extend your exposure at the state level.
• Idaho sales and use tax: The standard statute is also 3 years from the filing or due date, but it stretches to 7 years if no sales tax return was ever filed for the period in question.

If you have been through a federal audit that resulted in changes to your reported income, do not assume the matter is closed once the IRS finishes. Idaho may still have an open window to review your state return as a result. A tax preparation review can catch these overlaps before they become a second audit.

How Long You Should Actually Keep Your Tax Records

Given all of the above, here is a practical, no-guesswork breakdown for how long to hang onto your documents:

• 3 years: The baseline for most individual and business returns, in line with the standard federal and Idaho assessment periods.
• 6 years: If you have income sources that could plausibly be underreported by more than 25%, such as self-employment income, rental income, or investment gains, or if you hold foreign financial accounts.
• 7 years: Records related to a bad debt deduction or a loss from worthless securities.
• Indefinitely: Any year you did not file a return, filed a fraudulent return, or never signed a return. Also keep records tied to property (like your home or investments) for as long as you own the asset, plus the applicable statute period after you sell it.

Frequently Asked Questions

How Long Does The IRS Have To Audit You After You File?

The IRS generally has 3 years from the date you file your return, or its due date, whichever is later. This extends to 6 years if you omit more than 25% of your gross income, and there is no limit if you never filed or filed fraudulently.

Can The IRS Audit You After 7 Years?

In most cases, no. The standard window is 3 years, extended to 6 for substantial income omissions. Beyond 7 years, an audit is unlikely unless the return involved fraud or was never filed, in which case there is no expiration at all.

Does Filing An Extension Change The Audit Statute Of Limitations?

No. Filing with an extension and submitting your return by the extended deadline still starts the 3-year clock on the original due date, not the extension date.

What Happens If I Never Filed A Tax Return For A Past Year?

The statute of limitations never starts running for a year with no filed return, which means the IRS can assess tax for that year at any time. Filing a late return, even years after the fact, starts the clock and limits your long-term exposure.

Is Idaho's Audit Statute Of Limitations The Same As The IRS's?

They are similar but not identical. Idaho generally follows a 3-year rule for income tax, but a federal audit that changes your reported income can reopen Idaho's assessment window under Idaho Code 63-3068(f), and unfiled sales tax returns carry a 7-year statute rather than 3.

Should I Sign An Extension If The IRS Asks Me To During An Audit?

It depends on the situation. You are allowed to negotiate the terms, limit the scope, or decline. This is a decision worth making with a CPA who can weigh what is actually at stake in your specific audit before you sign anything.

How Long Should I Keep My Tax Records?

Keep records for at least 3 years for most returns, 6 years if you have income that could be underreported by more than 25% or foreign accounts, 7 years for bad debt or worthless securities claims, and indefinitely for any year you did not file or filed fraudulently.

Worried About An Audit Or An Old Return? Let's Look At It Together

Statute of limitations questions rarely come up in the abstract. Usually they come up because you got a letter, you are worried about an old return, or you are not sure how long to keep a box of records taking up space in your closet. Poston Denney & Killpack has been helping Idaho Falls individuals and businesses sort through exactly these situations since 1984, and we would rather look at your specific numbers than guess. If you are facing an audit or just want a second set of eyes on your filing history, call us at (208) 522-0886 or reach out through our IRS representation page to schedule a conversation.