IRS Notice CP12

We Corrected a Math Error on Your Return (CP12)

The IRS found and fixed a mistake on your return, which changed your refund amount.

Why you might get this

There was a math or entry error on your return.
A credit or payment you claimed was adjusted.
The correction changed your refund (up or down) from what you expected.

The deadline

There's no hard deadline to accept the correction, but if you disagree you generally have 60 days to tell the IRS before the change becomes final and harder to reverse.

Typical deadline — example only

ONE STEP — YOU HAVE TIME

There's no hard deadline to accept the correction, but if you disagree you generally have 60 days to tell the IRS before the change becomes final and harder to reverse.

Sep 1260 days left

CP12 · TAX YEAR 20XX · TYPICAL WINDOW

Solace

Illustrative only. Your real deadline is counted from the date printed on your own notice — decode yours to see the exact day.

Got this exact letter? Solace reads YOUR notice and tells you, in plain words, what it says, any deadline, and your next step — free, no account needed.

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What to do

Compare the IRS's corrected numbers to your original return, line by line.
If you agree, no reply is needed — expect your adjusted refund.
If you disagree, contact the IRS within 60 days to protect your right to challenge the change.
Keep the notice with your tax records.

What happens if you ignore it

If you do nothing, the correction stands. If it was wrong and you miss the 60-day window, fixing it becomes harder and may require an amended return or audit reconsideration.

A disagreement not resolved within 60 days may require filing an amended return or requesting audit reconsideration.

What the IRS CP12 notice means

A CP12 is usually good news wrapped in official-looking paper. It tells you the IRS found a math or entry error on your return, corrected it, and that the correction changed your refund. Often it means a larger refund than you expected — though it can go the other way too.

Because the IRS has already made the change, there's nothing you have to do if you agree. Your adjusted refund simply follows. But it's worth taking a few minutes to compare the corrected figures against your original return so you understand what changed and why. Common triggers include a mistyped number, a miscalculated credit, or a payment that posted differently than you recorded.

Here's the piece people miss: if you disagree with the correction, you generally have 60 days to tell the IRS. That 60-day window matters. Speak up in time and you keep the easy right to challenge the change and have it reviewed. Let the window close and the correction becomes final — undoing it later usually means filing an amended return or asking for audit reconsideration, which is slower and more work.

So a CP12 is low-stress, but not zero-attention: verify the numbers, and act within 60 days only if something looks wrong.

Solace can read notices like this for you and flag the quiet 60-day window, so a "good news" letter doesn't hide a decision you needed to make.

Got this exact letter? Solace reads YOUR notice and tells you, in plain words, what it says, any deadline, and your next step — free, no account needed.

Decode YOUR CP12 — free