You expected a refund of one amount. The deposit that arrived — or the notice that came instead of a deposit — shows a different number. A CP12 explains why.
The IRS found a math or calculation error on your return, corrected it, and in this case the correction worked in your favor — either increasing your refund or eliminating a balance you thought you owed. The CP12 is the notification of that correction.
What the CP12 means
CP12 is the mirror image of a CP11. Where a CP11 correction results in additional tax owed, a CP12 correction results in a larger refund or a reduced balance. The IRS made a change to your return during automated processing — typically a miscalculated credit, an arithmetic error, or an incorrectly applied deduction — and the corrected figures work out better for you than what you originally filed.
No immediate action is required if you agree with the change. The adjusted refund will be issued on the timeline shown in the notice.
What to do
Review the change described in the notice and compare it against your original return. If the correction looks right and the adjusted refund amount matches what the IRS calculated, no response is needed — the refund will arrive automatically.
If you believe the IRS correction was itself an error — meaning your original figures were actually correct — you have 60 days from the notice date to dispute it in writing. After 60 days the change becomes final.
Frequently asked questions
Do I need to do anything if I agree with the CP12? No. If the change looks correct, simply wait for the adjusted refund.
What if my refund is smaller than expected but I didn’t receive a CP12? A smaller-than-expected refund without a notice often indicates a refund offset — where the Treasury applied your refund to a prior debt. Check your IRS online account for any offset information.