The Standard Three-Year Window
For most tax returns, the IRS has three years to audit you after you file. This means if you filed your 2021 return in April 2022, the IRS generally cannot examine that return after April 2025. The clock starts from your filing date, not the tax year itself — so if you filed late, the three years runs from when you actually submitted the return.
This three-year rule applies to routine audits where the IRS is checking whether you reported income correctly, claimed deductions you were may have access to to, and calculated your tax liability accurately. During this window, the IRS can request documentation, ask questions about specific items on your return, and assess additional tax if they find errors.
Key Takeaways
- The IRS can audit returns within three years of filing in most cases, though this period can be extended if you underreported income or made substantial errors.
- If you underreported gross income by 25 percent or more, the IRS has six years to audit that return instead of three.
- The IRS has no time limit to audit if you filed a fraudulent return or did not file at all, and can go back as far as they have records.
- Keeping tax documents for at least three to six years protects you if questions arise, and longer for major items like home improvements or business assets.
- The statute of limitations is a legal protection that applies automatically — you do not need to do anything to invoke it.
When the IRS Can Go Back Six Years
If the IRS finds that you underreported your gross income by 25 percent or more, they can extend the audit window to six years. This is a significant threshold — it means you left off a substantial portion of income, not just a small mistake or a missed 1099 form. The six-year rule applies to the entire return, not just the underreported income.
For example, if your actual gross income was $100,000 but you reported only $70,000, that is a 30 percent underreport, and the IRS can audit that return up to six years after you filed. This rule exists because substantial income omissions suggest either carelessness or intent to evade taxes, and the IRS wants more time to investigate.
Fraud and Missing Returns Have No Time Limit
If the IRS suspects you filed a fraudulent return — meaning you intentionally misrepresented your income, deductions, or tax liability — there is no statute of limitations. They can go back as far as they have records, which in practice means many years or even decades. Fraud is a serious allegation and requires evidence of intent, not just error.
Similarly, if you did not file a return at all for a given year, the IRS can assess tax for that year at any time. There is no deadline for them to come after unfiled returns. This is why the IRS sometimes contacts people about returns from 10, 15, or even 20 years ago — because those years were never filed.
How the Statute of Limitations Clock Works
The clock starts on the date you file your return, not on April 15 or the actual tax year. If you file early in January, the three-year window begins then. If you file on April 14, it begins then. If you file an extension and submit your return in October, the clock starts in October.
The statute of limitations also pauses or extends in certain situations. If you and the IRS agree in writing to extend the audit period, the clock stops. If you file an amended return, a new statute of limitations period can begin for the items you changed. If you are out of the country for an extended period, the time you are absent may not count toward the limit.
Once the statute of limitations expires, the IRS cannot assess additional tax for that year. This is a legal protection built into tax law, and it applies whether or not you are aware of it.
What Records to Keep and for How Long
The IRS recommends keeping tax records for at least three years, which aligns with the standard audit window. However, many tax professionals suggest keeping records for six years to cover the extended window for substantial income underreports. For certain items, longer retention makes sense.
Keep records related to home purchases, major renovations, and business assets for as long as you own the property, plus three years after you sell it. The IRS can question the basis of your home or the depreciation you claimed on business property years after the original purchase. Keep records of large charitable donations, investment transactions, and business expenses for at least six years. If you are self-employed or own a business, the IRS may scrutinize multiple years of returns, so keeping seven years of records is common practice.
What Happens When the Statute Expires
Once the statute of limitations expires, the IRS cannot assess additional tax for that year through a standard audit. However, this does not mean the IRS forgets about you. If they suspect fraud, they can still investigate and potentially pursue criminal charges even after the civil statute expires, though criminal prosecution has its own time limits.
If you receive an audit notice after the statute of limitations has expired, you can raise this as a defense. The IRS is required to respect the statute, and an experienced tax professional or attorney can help you assert this protection. In practice, the IRS has systems to track which returns are still within the audit window, but errors happen.
State Tax Authorities May Have Different Rules
Your state tax authority operates under its own statute of limitations, which may be longer or shorter than the federal three-year window. Some states follow the federal rule, while others allow four, five, or even seven years for audits. A few states have no statute of limitations for fraud.
If you are audited by your state, the state's rules apply to state tax liability, separate from any federal audit. It is possible to be audited by the IRS within the federal window while also being audited by your state under a longer state window for the same tax year.
Frequently Asked Questions
Can the IRS audit me for a return I filed 10 years ago?
Only if you did not file a return for that year, if the IRS suspects fraud, or if you underreported gross income by 25 percent or more (which extends the window to six years). For a normal return filed 10 years ago, the statute of limitations has expired and the IRS cannot assess additional tax.
Does the statute of limitations reset if I file an amended return?
Filing an amended return can start a new statute of limitations period for the items you changed. The new period typically runs three years from the date you file the amended return. However, the original statute of limitations on the original return still applies to items you did not amend.
What if I agree to extend the audit period with the IRS?
You can agree in writing to extend the statute of limitations, giving the IRS more time to complete their examination. This is voluntary — you do not have to agree. However, the IRS may pressure you to sign an extension, and refusing can sometimes lead to a faster but less favorable resolution. A tax professional can advise whether extending is in your interest.
Does keeping records longer than three years hurt me?
No. Keeping records longer than the statute of limitations requires is purely protective and costs you nothing. If the IRS does contact you about an older return, having documentation makes it easier to respond and defend your position. There is no downside to retaining records longer than required.
Can the IRS go back further if I owe money?
The statute of limitations applies the same way whether you owe money or are owed a refund. The IRS cannot extend the window simply because you have a tax debt. However, if you do not pay the tax they assess, they can pursue collection for a longer period — the collection statute of limitations is typically 10 years from the date of assessment.