IRS Notice CP11: What It Means and What to Do
The IRS found what it considers a mistake on your tax return, corrected it, and the correction means you now owe money. This is called a math error notice. You can either pay the new amount or contact the IRS by the date on the notice if you think the change is wrong.
CP11 key facts
| Official name | We corrected one or more mistakes on your tax return. As a result, the amount you owe has changed. (IRM title: Math Error on Return - Balance Due) |
|---|---|
| Who gets it | Individuals |
| Severity | 3 of 5: Moderate: respond by the deadline A balance is due and the right to have the change formally reversed ends at the notice deadline, but no enforcement action has started. |
| Response window | Contact the IRS at the number on the notice by the date indicated. Under IRC 6213(b)(2)(A), as described in IRM 21.5.4.3, you have 60 days from the date of a math error notice to request abatement of the additional tax. To avoid interest, pay in full by the due date shown on the notice. |
| Deadline basis | The date printed on the notice. |
Severity is RAHA Financials' own 1 to 5 rating of how urgent the notice usually is. It is not an IRS classification.
How long do I have to respond to a CP11?
Use the date printed on your notice. It is typically 60 days from the notice date. Enter the notice date to see an approximate date.
The date printed on your notice always controls. Open CP11 in the IRS Notice Decoder.
Why did I get a CP11?
Common reasons include:
- An arithmetic or calculation error on the return
- A credit or deduction amount that did not match the IRS's figures or supporting entries
- Numbers carried incorrectly from one form or schedule to another
- Inconsistent entries on the return that the IRS corrected during processing
What should I do?
- Read the notice, especially the section explaining what the IRS changed on your return and how it affects the amount you owe.
- Compare the change against your copy of the return and your records.
- If you agree, pay the amount owed by the date on the notice (for example, through IRS Direct Pay or your IRS Online Account) to limit interest.
- If you can't pay in full, pay what you can and look into a payment plan (online, or with Form 9465).
- Correct your own copy of the return for your records; do not send it to the IRS.
- If you disagree, call the number on the notice before the date shown and have your return and supporting documents ready.
What documents do I need?
- The CP11 notice
- Your copy of the tax return for the year shown
- Forms and schedules related to the changed line (for example, W-2s, 1099s, credit worksheets)
- Records of any payments already made for that year
What should I avoid?
- Don't let the deadline on the notice pass if you disagree; after it you lose the formal right to have the change reversed.
- Don't send a corrected copy of your return in response; the IRS says to keep it for your records.
- Don't ignore the balance, since interest may continue to build until it is paid.
What if I disagree with a CP11?
Contact the IRS at the number shown on the notice by the date indicated. Per the IRS page, if you don't contact them by that date you lose formal rights to have the change reversed and your right to appeal to the U.S. Tax Court. Under IRC 6213(b)(2)(A) (IRM 21.5.4.3) a request for abatement is due within 60 days of the notice date; requests after that are generally handled under the IRS's claim procedures, and further corrections are made with Form 1040-X.
What happens if I ignore a CP11?
If you don't pay, interest generally continues to accrue on the unpaid balance and the IRS may send further balance-due notices. If you don't dispute the change by the deadline, you generally lose the formal right to have it reversed and to appeal to the U.S. Tax Court, though you may still be able to seek a correction through an amended return or claim.
What else should I know about CP11?
A CP11 is a math error notice, which lets the IRS assess extra tax without first sending a notice of deficiency. The trade-off is a short, statutory dispute window: IRC 6213(b)(2)(A) gives you 60 days from the notice date to request abatement (IRM 21.5.4.3), and a timely request generally makes the IRS reverse the assessment and use normal deficiency procedures if it still wants the tax, which preserves your Tax Court rights. The IRS also may not levy for the assessment during that 60-day period. After the window closes, the change stands unless you seek relief through claim procedures such as an amended return, so disputing early matters more than with many other notices.
Want a professional to handle your CP11 response?
IRS Notice Response Plan
Fixed price, quoted before any work startsFixed fee.
- Review of your notice and account transcript
- A written plan: agree, partly agree, or dispute
- Draft response and list of supporting documents
- Deadline tracking so nothing lapses
CP11: frequently asked questions
What if I disagree with the changes?
Call the IRS at the number on your notice before the date shown. If you miss that date, the IRS says you lose formal rights to have the changes reversed and your right to appeal to the U.S. Tax Court.
Will I be charged interest?
The IRS says paying the full amount by the due date on the notice avoids interest charges. Unpaid amounts generally keep accruing interest.
What if I need to make another correction to my return?
The IRS says to file Form 1040-X, Amended U.S. Individual Income Tax Return.
Can the IRS levy while I'm disputing?
Under IRC 6213(b)(2)(B), as described in IRM 21.5.4.3, the IRS may not levy or go to court to collect the math error assessment during the 60-day period after the notice.
