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Understanding an IRS CP12 Notice

CP12 means the IRS changed your return due to a math or credit error. Your refund changed. Check the math before cashing the check.

Herman Viglione, EA
Written by
Herman Viglione, EA
Updated April 22, 2026
30-day response window

IRS notices have short response windows. Call the office today if your deadline is close.

What was changed

The notice lists the specific change. Common CP12 triggers: EIC calculation, Child Tax Credit, education credits, dependent issues, or transcription errors. The IRS usually gets the math right, but not always.

If you disagree

You have 60 days to contest the change. Respond in writing with documentation. If the 60 days pass without contest, the change becomes final.

Have a specific situation?
Call the office and a human answers.

Common questions

Can I cash the refund check if I disagree?
Yes, cashing it doesn't waive your right to dispute. But respond within 60 days to preserve the argument.

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