IRS CP11: what it means and what to do
The IRS corrected one or more mistakes on your tax return, and as a result the amount you owe has changed. This summary is drawn from the IRS page for the CP11, last checked on October 13, 2026.
Why you received a CP11
- The IRS found and corrected one or more mistakes on your tax return
- The correction changed the amount you owe
What to do
- Read the notice to see what changed and how it affects your balance
- If you agree, pay the amount owed by the date on the notice
- If you can't pay in full, set up a payment plan
- Correct your own copy of the return but don't send it to the IRS
- If you disagree, contact the IRS at the number on the notice by the date indicated
Deadline: By the date indicated on your notice
If you disagree, or do not respond
Call the toll-free number in the Where to find more information section of the notice; many errors can be fixed by phone and missing documents can be faxed during the call. If the IRS doesn't receive support for your original return, your case may be referred for audit, and audit staff would contact you within 6 weeks.
You lose your formal rights to have the changes reversed and to appeal to the U.S. Tax Court. The IRS will still consider documentation sent after the deadline and may reverse the changes if it agrees.
Get your records together first
Most notices come down to matching what the IRS has on file against your own records. Before you reply, pull the return the notice refers to, the bank statements and income forms for that year, and any payment confirmations. If your books are reconciled to the bank, that comparison takes minutes instead of days.
Source and verification
IRS: Understanding your CP11 notice →
Last verified against that page on October 13, 2026. This is general information, not advice for your situation. The notice itself is the authority on your amounts and dates. Talk to a CPA or enrolled agent if the amounts are large or you are unsure.
Related
- All IRS notices explained
- IRS CP2000 — The IRS is proposing changes to your tax return because income or payment information it received from third parties does not match what you reported.
- IRS CP14 — The IRS says you owe money on unpaid taxes.
- IRS CP501 — This is a reminder that you still owe a balance on one of your tax accounts.
- IRS CP503 — This is your second reminder that you have an unpaid balance on one of your tax accounts, because the IRS hasn't received your payment or a response to earlier notices.
- IRS CP504 — This is a Notice of Intent to Levy under Internal Revenue Code section 6331(d) and a final reminder that the IRS may levy your wages, bank accounts, or state tax refund for an unpaid balance.
- IRS LT11 — The IRS has not received payment for overdue taxes and intends to seize your property or rights to property.
- Find an accountant — for help responding.
Frequently asked questions
What is an IRS CP11 notice?
The IRS corrected one or more mistakes on your tax return, and as a result the amount you owe has changed.
How long do I have to respond to a CP11?
By the date indicated on your notice Check the date printed on your own notice, which is the one that applies to you.
What happens if I ignore a CP11?
You lose your formal rights to have the changes reversed and to appeal to the U.S. Tax Court. The IRS will still consider documentation sent after the deadline and may reverse the changes if it agrees.
What if I disagree with the CP11?
Call the toll-free number in the Where to find more information section of the notice; many errors can be fixed by phone and missing documents can be faxed during the call. If the IRS doesn't receive support for your original return, your case may be referred for audit, and audit staff would contact you within 6 weeks.
How can I find out what caused the change?
Check the What we changed on your return section of the notice, or call the number listed on it.
Will I be charged interest?
Paying in full by the due date avoids more interest; otherwise interest accrues on the unpaid balance from the original return due date.
What if I can only pay part of what I owe?
A late payment penalty applies. If circumstances beyond your control prevent payment, contact the IRS by the notice due date; the penalty may be removed.
How do I make another correction to my return?
File Form 1040-X, Amended U.S. Individual Income Tax Return.
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Authoritative sources
US tax rules change every filing season. Always verify the current position with the official sources below before filing.
- IRS — irs.govInternal Revenue Service. Forms, publications, due dates, and current-year thresholds for federal income tax, payroll tax, and 1099 reporting.
- IRS — Forms & InstructionsCanonical PDF forms (W-4, W-9, 1099-NEC, 1040-ES, 941, 940, W-2, W-3) with current-year instructions.
- SSA — Business Services OnlineSocial Security Administration portal for W-2 / W-3 e-filing, EIN verification, and AccuWage validation.
- Streamlined Sales Tax — streamlinedsalestax.orgMulti-state Streamlined Sales and Use Tax Agreement (SSUTA) — registration in 24 SST member states with one application.
- Tax Foundation — Sales Tax & NexusIndependent state-by-state research on sales tax rates, economic nexus thresholds, and franchise / margin tax structures.
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