The IRS does not have unlimited time to act. The law sets three main deadlines, called statutes of limitations:
- Assessment: how long the IRS has to decide you owe more tax, usually after an audit or a review.
- Collection: how long the IRS has to collect a tax once it is on the books.
- Refunds: how long you have to claim money back.
Each has its own name and rules. When a deadline passes, the IRS generally can no longer assess or collect the tax, and you can no longer claim a refund. But the exceptions are important, and the dates are often later than people expect.
The three clocks at a glance
| Clock | General rule | IRS name |
|---|---|---|
| Assessing more tax | 3 years after the return is filed or due, whichever is later | Assessment Statute Expiration Date (ASED) |
| Collecting tax | 10 years after the tax is assessed | Collection Statute Expiration Date (CSED) |
| Claiming a refund | 3 years after filing, or 2 years after paying, whichever is later | Refund Statute Expiration Date (RSED) |
How long the IRS has to assess more tax
The IRS can usually assess more tax within 3 years after your return was due (including extensions) or, if you filed late, within 3 years after the IRS received it, whichever is later.
IRS examples. You filed your 2021 return on the due date, April 18, 2022. The assessment deadline was April 18, 2025. If you instead filed late on October 31, 2022, after the October 17, 2022, extended due date, the deadline was October 31, 2025.
When the IRS gets more time:
- You did not file. The IRS can assess at any time, including through a substitute for return it prepares for you. Filing your own return starts the 3-year clock. See unfiled tax returns.
- You left out more than 25% of your income. The period is 6 years (Internal Revenue Code section 6501(e)).
- Fraud. If you filed a false or fraudulent return to avoid tax, there is no time limit.
- You agreed to extend it. During an audit the IRS may ask you to sign an agreement extending the deadline. You can negotiate the terms or refuse. Publication 1035 explains the process. See IRS audits.
When the clock is paused: if the IRS sends a notice of deficiency (the "90-day letter," such as a CP3219A), assessment is suspended while you have the right to go to Tax Court, and for 60 days after a final Tax Court decision. Some bankruptcy situations also pause it.
How long the IRS has to collect
Once tax is assessed, the IRS generally has 10 years to collect it, plus penalties and interest. Each assessment has its own CSED. Your original return, an amended return and an audit adjustment for the same year can each have a different date.
What pauses or extends the 10-year clock
The IRS lists these common situations:
| Event | Effect on the CSED |
|---|---|
| Payment plan request | Paused while pending; 30 more days if rejected, withdrawn or terminated; paused during an appeal |
| Offer in compromise | Paused while pending; 30 more days if rejected; paused during an appeal |
| Collection Due Process hearing | Paused from your request until the determination is final; if less than 90 days remain afterward, extended to 90 days |
| Bankruptcy | Paused from the petition until the case ends, plus 6 months |
| Innocent spouse request | Paused until the Tax Court window or case ends, plus 60 days (for the requesting spouse only) |
| Living outside the U.S. 6 months or more | Generally paused for that time |
| Combat zone or military service | Paused for the service period plus extra time |
Once a payment plan is in effect, the clock runs normally (Topic 202). An equivalent hearing does not pause it (Publication 594). Currently Not Collectible status is not on the IRS's list of events that pause the clock.
How a pause adds time. Say tax was assessed June 1, 2026. With no pauses, the CSED would be June 1, 2036. Now say you submit an offer in compromise on January 4, 2027, and it is rejected on July 2, 2027, with no appeal. That is 179 days pending plus 30 days after rejection, or 209 days. The CSED would move to about December 27, 2036. Real cases can include several pauses.
How to find your CSED
- Get your account transcript for the tax year through your IRS Online Account, Form 4506-T, or the automated line at 800-908-9946. See IRS transcripts and Online Account.
- Look at the Transactions section. The IRS says to look for a 3-digit transaction code with a date below it. Generally, this date is the CSED plus any time added by law.
- If you are unsure, call the number on your latest notice and ask the IRS to confirm the last day it can collect for each period.
- If you think the IRS computed your CSED wrong, ask it to explain. If that does not resolve it, request help from the Taxpayer Advocate Service with Form 911.
What happens when the CSED passes
The IRS generally can no longer collect that assessment, and any federal tax lien for it is released automatically. If a levy on future income was served before the CSED, the IRS can keep receiving payments from that levy. If you paid after the CSED expired, you may be able to get that money back if you claim it before the refund deadline.
"Waiting out" the IRS is risky. Many common actions, such as asking for a payment plan or offer, filing for bankruptcy or requesting a hearing, add time to the clock. Meanwhile interest and penalties keep growing, refunds are kept, and liens and levies remain possible. Talk with a tax professional or Low Income Taxpayer Clinic before making decisions based on a CSED.
How long you have to claim a refund
You generally must claim a credit or refund by the later of:
- 3 years from the date you filed the original return, or
- 2 years from the date you paid the tax.
A return filed early is treated as filed on the due date. Withholding and estimated payments are treated as paid on the due date.
How much you can get back:
- If you claim within 3 years of filing, the refund is limited to what you paid in the 3 years before the claim, plus any extension time.
- If you claim later, under the 2-year rule, the refund is limited to what you paid in the 2 years before the claim.
Refund example. If you filed your 2023 return on its due date, April 15, 2024, and want to amend it to claim a missed credit, you generally have until April 15, 2027, to file the claim.
Exceptions that give more time include agreeing in writing to extend the assessment period (the agreed period plus 6 months), being affected by a federally declared disaster (up to 1 more year), serving in a combat zone, and claims based on a bad debt or worthless security (7 years from the return due date).
Claim an income tax refund on your original return or an amended return (Form 1040-X). Use Form 843 for other taxes and penalties.
Frequently asked questions
How far back can the IRS audit me?
Usually 3 years from when you filed (or the due date, if later). It is 6 years if you left out more than 25% of your income, and there is no limit for fraud or for years you did not file.
Does the 10-year collection period ever restart?
Each new assessment gets its own 10-year period. For example, an audit adjustment for an old year starts a new CSED for the added tax. Pauses for things like offers and bankruptcy add time to the existing clock rather than restarting it.
Does a payment plan extend the collection deadline?
The clock pauses while your request is pending, for 30 days after a rejection or proposed termination, and during an appeal. Once the plan is in effect, the clock runs normally.
Can I still get a refund for a year I never filed?
Possibly, but time matters. For a year you never filed, the original return is your refund claim. The refund is limited to tax paid in the 3 years before you file (plus any extension period), and withholding and estimated payments count as paid on the return's due date. So in general you must file within 3 years of the original due date to get that money back. See unfiled tax returns and refund delays and offsets.
Where can I get help with a statute question?
Statute dates can be complicated. A CPA, enrolled agent, tax attorney or Low Income Taxpayer Clinic can review your transcripts. See choosing a tax professional.
Sources
- Internal Revenue Service (IRS), "Statutes of limitations for assessing, collecting and refunding tax". irs.gov
- IRS, "Time IRS can assess tax". irs.gov
- IRS, "Time IRS can collect tax". irs.gov
- IRS, "Time you can claim a credit or refund". irs.gov
- IRS, Publication 594, "The IRS Collection Process" (Rev. 1-2026). irs.gov
- IRS, Topic no. 202, "Tax payment options". irs.gov
- IRS, Publication 1660, "Collection Appeal Rights" (Rev. 1-2020). irs.gov
IRSV.com is an independent guide and is not affiliated with the IRS. This page is general information, not tax or legal advice. Rules change; confirm details on IRS.gov or with a tax professional. Found an error? Tell us.
