When the IRS “corrects” your return it sends a math-error notice: CP11 (the change means you now owe), CP12 (the change adjusted your refund up or down), or similar. These often involve credits like the Child Tax Credit, Recovery Rebate, or EITC, or a mismatch in payments claimed. You can disagree and ask them to reverse it.
Deadline: to preserve your right to dispute (and your Tax Court rights), request the IRS reverse the math-error adjustment within 60 days of the notice date. After 60 days you can still pursue it, but only through the harder refund-claim or deficiency route.
Before you write
Recompute the line(s) the IRS changed and compare to your filed return. Common real errors: a dependent’s SSN or a credit was disallowed in error, a payment you made wasn’t counted, or the IRS misread a figure.
The letter
[Your name]
[Address]
[City, State ZIP]
[Daytime phone]
[Date]
Internal Revenue Service
[Use the address on your CP11/CP12 notice]
Re: [CP11 / CP12] math-error notice - request to reverse the adjustment
Name: [Your name] SSN/ITIN: [xxx-xx-1234]
Tax year / form: [year / 1040] Notice date: [date]
To whom it may concern:
I disagree with the math-error change made to my [year] return and request that
you reverse the adjustment within the 60-day period. The change is incorrect
because:
- [e.g. "You disallowed the Child Tax Credit for [dependent], but [he/she] is a
qualifying child with SSN [xxx-xx-1234]; see attached."]
- [e.g. "You reduced my refund for an estimated payment of $[ ] made on [date];
proof is enclosed."]
- [explanation], see attached [document].
Please reverse the adjustment and restore the figures from my filed return, or
send me a detailed explanation of the change. Enclosed: [supporting documents].
Sincerely,
[Signature]
[Printed name]
How to send it
Send within 60 days, by certified mail with return receipt to the address on the notice, with copies of your proof. You can also call the number on the notice for a quick fix. Keep a full copy.
Notes. Requesting reversal within 60 days matters: it forces the IRS to follow normal deficiency procedures (preserving your Tax Court rights) rather than simply assessing the tax. If you agree with the change, no response is needed — just pay any balance or expect the adjusted refund. General information, not tax advice.