Most people assume that once a few years have passed, old tax returns are safe. That’s mostly true — but the exceptions matter, and some of them have no limit at all.

Understanding the statute of limitations on IRS audits tells you how long you need to keep records, when you can stop worrying about an old return, and which situations keep the window open far longer than you’d expect.

The Standard Rule: Three Years

The general statute of limitations for IRS audits is three years from the later of two dates: the date you filed your return, or the due date of the return (including extensions).

If you filed your 2022 return on April 15, 2023, the IRS generally has until April 15, 2026 to assess additional tax. If you filed on October 15, 2023 (with an extension), the three-year clock runs from that date.

This three-year window covers most of what the IRS actually examines. Routine audits — correspondence audits, office audits, and most field audits — happen within this window. If you’ve filed accurately and maintained your records for three years after filing, you’re protected for the standard case.

The Six-Year Extension

There’s a significant exception that catches many people off guard: if you omit more than 25% of your gross income from a return, the statute of limitations extends to six years.

This isn’t about intentional fraud — it applies even if the omission was accidental. An investor who fails to report sale proceeds from a brokerage account, a self-employed person who misses a large 1099-NEC, or a partner who doesn’t report all passthrough income could inadvertently trigger the six-year window.

“Gross income” for this purpose is broadly defined, and courts have generally interpreted it expansively. The 25% threshold sounds high, but on a $300,000 gross income return, omitting $75,001 or more triggers six years. That’s not an unusual amount for an investor or business owner who misreports investment income.

No Limit: Fraud and Failure to File

Two situations have no statute of limitations at all:

Fraudulent returns: If the IRS can establish that you filed a fraudulent return — one where you intentionally misreported income or claimed false deductions — there is no time limit on their ability to assess tax. None. The IRS can go back to any year.

Failure to file: If you never filed a return for a given year, the statute of limitations never starts. The IRS can assess tax on an unfiled year at any point. This is why unfiled returns from years past carry ongoing risk until the returns are actually filed.

These two exceptions are why tax professionals sometimes say there’s no such thing as an “old” tax problem if it involves fraud or non-filing.

What the Statute Covers — and What It Doesn’t

The statute of limitations limits the IRS’s ability to assess additional tax — it doesn’t eliminate their ability to examine information. The IRS can look at records relevant to open years even if those records involve closed years. A cost basis established in 1995 is still relevant when you sell the asset in 2025.

For refund claims, different rules apply. You generally have three years from the original return due date (or two years from when you paid the tax, whichever is later) to file an amended return claiming a refund. Miss that window, and the IRS can keep the money.

How Long You Should Actually Keep Records

Given these rules, here’s a practical record-keeping guide:

Keep for at least 3 years from filing:

• W-2s, 1099s, and other income documentation
• Receipts and records for deductions claimed
• Bank statements supporting reported income

Keep for at least 6 years:

• Records supporting any large transaction — investment sales, business asset sales, property transactions
• Records where there’s any possibility of underreported gross income

Keep indefinitely:

• Records supporting cost basis on assets you still own
• Records related to any year where a return was not filed
• Records related to retirement account contributions and basis (Form 8606)
• Any records related to a tax controversy that hasn’t been fully resolved

Frequently Asked Questions

Q: Does the statute of limitations restart if I amend a return?
A: An amended return extends the statute only in limited circumstances — generally, the IRS has three years from when you filed the amended return (or the original three years, whichever is later) to assess tax related to the amendment. Amending doesn’t give the IRS a fresh three years to examine the entire return.

Q: What if the IRS audits me after the statute has closed?
A: If the IRS attempts to assess tax after the statute has run, you can raise the limitation as a defense. This requires you to know the law and assert it — the IRS is not required to tell you the limitation has expired.

Q: Does the statute apply to payroll taxes?
A: Yes, with the same general rules — three years from filing (or due date), six years for substantial understatement, no limit for fraud or non-filing.

Q: Can the IRS and taxpayer agree to extend the statute?
A: Yes. The IRS frequently requests that taxpayers sign Form 872, consenting to extend the statute of limitations. You have the right to refuse, but refusal typically results in the IRS accelerating its examination to beat the closing deadline — which is usually not in the taxpayer’s interest.

The statute of limitations gives you legal protection, but only if you understand which version applies to your situation. Accurate filing, thorough record-keeping, and prompt resolution of any notices are the cleanest way to ensure you’re never looking at an open window you didn’t know existed.

If you’d like to apply this to your situation, the team at Molen & Associates is here to help. Schedule a consultation at molentax.com.