IRS notice
IRS Notice CP11: The IRS Changed Your Return and You Owe
The IRS corrected what it sees as a math or similar error, leaving a balance due. You have 60 days to dispute and have it reversed.
Reply by the date on the notice
You have 60 days from the notice to request that the correction be reversed (IRC 6213(b)(2)); the date on the notice reflects it, and the right is lost after that.
This deadline is set by law and cannot be extended.
A CP11 says the IRS corrected one or more mistakes on your return and, as a result, you owe money. It is a math error notice: if you contact the IRS within 60 days of the notice, the law requires the IRS to reverse the change, and it can only reassess through the normal audit and deficiency process. If you agree, pay by the date on the notice; if you don't, call the number on the notice before the date passes.
What this notice is telling you
- The IRS found what it treats as an error on the return, such as a miscalculation, a figure that doesn't match a schedule, or a credit claimed without required information.
- It corrected the return under its math error authority without an audit, and the correction created a balance due.
- The notice's "What we changed on your return" section shows each change.
- Interest on the unpaid amount runs from the return's original due date, and a late payment penalty applies if it isn't paid.
What to do
Read the changes section first
Compare each change to your return and your records. Many corrections are right; some come from a missing form or a number the IRS couldn't match.
If you agree, pay by the date on the notice
Paying by then avoids additional penalty and interest. If you can't pay in full, set up a payment plan. Update your own copy of the return; don't mail it to the IRS.
If you disagree, call within the 60 days
The IRS says the phone is the fastest way to resolve many return errors, and you may be able to fax missing documents during the call. You don't have to prove anything to get the change reversed, but documents can speed things up.
Keep proof of when you contacted the IRS
Note the date and the representative's ID if you call, or keep the postmark if you write. Timeliness is what triggers the automatic reversal.
Expect an audit letter if support is thin
If you dispute without showing support for the original figure, the IRS may refer the return to examination. The IRS says audit staff would contact you within about six weeks.
Why the 60-day window matters on a CP11
A math error notice is not a notice of deficiency, so it doesn't open a Tax Court petition right by itself. What it gives you instead is a statutory right to request abatement within 60 days. If you do, the IRS must abate the assessment, even without substantiation, and any reassessment has to go through deficiency procedures, which means an examination and a notice of deficiency with Tax Court rights. Miss the 60 days and you lose that formal right: the IRS will still look at documents you send later and may reverse the change if it agrees, but it isn't required to.
| Within 60 days | After 60 days | |
|---|---|---|
| Will the change be reversed? | The IRS reverses most changes that increased what you owe | Only if the IRS reviews your documents and agrees |
| Need documents? | Not required, though they can speed things up | Yes, in practice |
| Tax Court route | Preserved: any reassessment needs a notice of deficiency | Lost for this correction |
A 2025 law change to these notices
The Internal Revenue Service Math and Taxpayer Help Act (Pub. L. 119-39, enacted 25 November 2025) requires math error notices to explain the error in detail, name the line or schedule involved, give the reason for the adjustment, and state the 60-day right with the exact deadline date. It applies to notices sent starting 12 months after enactment, so CP11 notices from late 2026 onward should show the exact date to act.
If you can't pay
If you agree but can't pay in full, a payment plan is available, and if circumstances beyond your control kept you from paying, contact the IRS by the notice date and ask about penalty relief.
Where this notice sits
The usual order. Not every account gets every notice, and some steps can be skipped.
Want a CPA to deal with it?
Bring the notice to a free consultation, in person on James Island or by video. We read it with you, tell you what it means for your account and, if you want us to, take over the response once you sign Form 2848.
IRS & SCDOR letters — Find your notice number below, see what it means and which date matters, then let a licensed CPA deal with the IRS or SCDOR on your behalf.
Sources
By Haigler CPA Group. Updated . Notices are revised from time to time, so go by the wording and dates on your own notice. The information on this site is general in nature and is not tax, legal, or accounting advice for your situation. Tax law changes and the right answer depends on facts we would need to review with you. Please speak with a qualified professional before acting on anything you read here.
Questions about CP11
Do I have to prove the IRS is wrong to reverse a CP11 change?
No, not if you contact the IRS within the 60 days. The IRS says you don't have to explain or send documents, though doing so may speed up the process. Without support, it may send the return to audit.
Can I file an amended return instead of calling about a CP11?
Form 1040-X is for further corrections you want to make. To dispute the IRS's change itself, contact the IRS at the number on the notice by the deadline.
Will I owe interest on a CP11 balance?
Yes. Interest accrues on the unpaid balance from the date the return was due, not from the notice date, until it is paid.
My tax software made the error. Should I fix next year's return?
Correct your copy of this year's return and, if a preparer filed it, ask them to correct theirs, so the same figure doesn't carry forward.
Other notices
- CP12: We corrected your return and your refund changedThe IRS corrected your return and changed your refund, or created one. Agree and do nothing, or dispute within 60 days.
- CP22A: Changes to your return left a balance dueThe IRS adjusted your return, often based on information you gave it, and the result is a balance due. Pay or call by the date on the notice.
- IRS notice lookupEvery IRS notice carries a code. Find yours below to see what it generally means, which date matters, and what to do before that date passes.
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