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IRS CP12: Math Error Correction — Refund Adjusted

Informational — severity 1/5

Straight answer: A CP12 means the IRS found a calculation error on your return and corrected it, changing your refund amount. If you agree, you do nothing and the corrected refund arrives.

How many days do I have to respond to a CP12?

60 days from the date printed on the notice (not the day you opened it). You have 60 days to dispute the correction if you disagree — after that, reversing it requires a formal amended-return or audit-reconsideration process.

What should I do right now?

  1. Compare the IRS's correction against your return to see what changed.
  2. If you agree: no action needed.
  3. If you disagree: call or write within 60 days and ask for reversal — the burden at this stage is low.

The costly mistake people make with a CP12

Blowing past the 60-day dispute window on a correction that's actually wrong. Math-error authority lets the IRS change returns without audit — but the 60-day reversal right is your easy undo.

Do I need professional help with a CP12?

Rarely needed unless the adjustment involves credits (EIC, CTC) you believe you qualify for — those denials are worth contesting with help.

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