IRS CP12 Notice: Math Error — Refund Changed
A CP12 notice means the IRS corrected an error on your return and changed your refund amount — often larger or smaller than expected — and no response is needed unless you disagree.
Deadline calculator
The CP12 clock runs from the date printed on the notice — not the day you opened it.
Estimate only, based on the standard 60-day CP12 window. Your notice controls — always use the specific date printed on it.
What a CP12 actually means
The IRS adjusted something — a credit calculation, withholding transcription, or an offset of estimated payments — and your refund changed as a result. If you agree, you simply wait for the adjusted refund (typically 4–6 weeks).
If the correction cut a credit you're actually entitled to, don't let it slide: you have 60 days to ask for reversal with full appeal rights, which is far easier than filing a refund claim later.
What to do, step by step
- 1Read what was changed and compare it to your filed return.
- 2If you agree, no action — the corrected refund arrives by the method you chose.
- 3If you disagree, contact the IRS within 60 days with documentation to request reversal.
- 4If the refund doesn't arrive in 6 weeks, check your IRS online account or 'Where's My Refund'.
Common questions
My CP12 lowered my refund — is that final?+
Not if you act within 60 days. Request abatement with documentation and the IRS must reverse and use normal procedures if it still disagrees. After 60 days, you'd have to pursue a formal refund claim.
Received a CP12? Get it handled.
Talk to a tax specialist about your notice — free, no pressure, no judgment.