Tax · United States
IRS Notice CP11 — the IRS corrected your return, and a balance is due
A CP11 means the IRS corrected one or more mistakes on your tax return under its 'math error' authority, and the correction created a balance due. A strict 60-day window exists to object and have the change reversed without paying first.
How serious: routineAlso called: CP11, math error notice (balance due), return correction notice
The IRS sends a CP11 when it corrected one or more mistakes on a tax return — miscalculated credits, wrong SSN or ID entries, arithmetic errors — and the result is a balance due.
The correction is applied automatically under the IRS's 'math error' authority. The notice shows the corrected figures and a payment due date.
The key protection is time-bound. If the IRS is contacted within 60 days of the notice date, it will reverse the changes made to the account; after that window, the formal rights change sharply.
Who sends it
The Internal Revenue Service (IRS) — the United States federal tax authority, part of the Department of the Treasury.
The code 'CP11' is printed in the top corner. The wording runs 'We corrected one or more mistakes on your tax return. As a result, the amount you owe has changed' or 'Changes to your tax return — amount due'. The notice shows the corrected figures and a payment due date.
The deadline
60 days from the date of the notice to dispute the correction ('If you contact the IRS within 60 days of the date of this notice, the IRS will reverse the changes made to your account' — TAS); payment of the new balance is due by the date shown on the notice
Two dates matter. Payment of the new balance is due by the date shown on the notice, and there are 60 days from the date printed on the notice to dispute the correction — within that window, the IRS will reverse the changes made to the account.
If you do nothing
The change becomes final. Without contact by the date shown on the notice, the formal right to have the changes reversed is lost, along with the right to appeal the decision to the U.S. Tax Court. After the 60 days, the remaining route is to pay the additional tax and then file a claim for refund (within 3 years from filing or 2 years from the last payment). Interest accrues on the unpaid balance and a late-payment penalty applies.
How it escalates
- 01After 60 days: loss of the right to automatic reversal and of pre-payment Tax Court appeal rights.
- 02Interest accrues from the return due date, and a late-payment penalty applies on the unpaid balance.
- 03The unpaid balance enters the IRS collection notice sequence (reminders, lien, intent to levy).
Common questions
What does the 60-day window give?
If the IRS is contacted within 60 days of the notice date, it will reverse the changes made to the account — or forward the case to Examination, which provides formal appeal rights including court review. No payment is required first within that window.
What happens once the 60 days pass?
The formal rights to reversal and to a pre-payment Tax Court appeal are lost. The remaining route is to pay the additional tax and then file a claim for refund, within 3 years from filing or 2 years from the last payment.
Why did the IRS change the return at all?
Under its 'math error' authority the IRS corrects certain mistakes automatically — common triggers are miscalculated credits, wrong SSN or ID entries, and arithmetic errors.
Sources
Facts verified against the sources below on 28 August 2026.