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IRS notice decoder · Corrections the IRS made

CP12: the IRS corrected your return and your refund changed

A CP12 says the IRS fixed a mistake on your return and your refund changed. If you agree, do nothing; if not, call by the date on it.

By the Carry Forward Learning team Reviewed by Hunter Nottingham, JD, CPA

No dated figures Checked Review by

CheckedOct 19, 2026

What a CP12 means

A CP12 means the IRS corrected one or more errors on your return, and now you either have a refund or a different refund than you expected. source 1

Under federal law, a math or clerical error notice isn't a notice of deficiency. The IRS can assess the corrected tax right away, and you can ask it to abate that assessment within a set period after the notice. If you ask in time, the IRS must abate it, and any reassessment has to go through the normal deficiency process. source 2

A smaller refund than you expected isn't automatically wrong. Find the changed line first, then decide.

The date that counts

If you disagree, contact the IRS at the number on the notice by the date listed on it. If you don't contact the IRS by the date on the notice, the IRS says you lose formal rights to have the changes reversed and your right to appeal to the Tax Court. Documents sent later are still considered, and the IRS may reverse the change if it agrees. source 1

Why people get one

  • A credit was figured differently from what the IRS's records support.
  • An arithmetic or transfer error changed the refund.
  • You expected to owe or break even, and the correction created a refund. source 1

First steps

  1. Read the part of the notice that lists what changed and compare it with your return. source 1
  2. Check your IRS online account, typed in yourself at irs.gov, to see the notice and your balance or payments.
  3. If you agree, there's nothing to send. The IRS says the refund should follow unless you owe other taxes or debts it must collect. source 1
  4. If you disagree, call the number printed on your notice by the date shown. The IRS says it usually reverses changes that reduced the refund you asked for. source 1
  5. Update your own copy of the return, but don't send that copy to the IRS. source 1

What not to do

  • Don't miss the date if you disagree. source 1
  • Don't pay or send documents through a link or phone number in an unexpected email or text. Use irs.gov, typed in yourself.
  • Don't assume the original refund amount is coming. Plan around the corrected one until it's settled.
  • Related CP11 A correction that leaves a balance due.
  • Related CP13 A correction that leaves the account at zero.
  • Related CP10 A correction that changes the estimated tax carried to next year.

Keep reading

Questions

Why did I get a CP12?

The IRS corrected errors on your return, and your refund is different from what you expected, or you have a refund when you expected to owe or break even. source 1

What if I disagree with a CP12?

Call the number on your notice by the date on it. The IRS says it will usually reverse changes that reduced your requested refund, and you don't have to send documents, though they can speed things up. source 1

Could a CP12 lead to an audit?

The IRS says that if it doesn't get information supporting your original return, it may send the case for audit, and audit staff would then contact you. source 1

Sources

  1. IRS, Understanding your CP12 notice (including CP12, CP12E, CP12F, CP12G, CP12N, and CP12U) (updated August 11, 2026) (external site) checked Oct 19, 2026
  2. 26 U.S.C. section 6213 (deficiency procedures; math and clerical errors) (external site) checked Oct 19, 2026

Every rule on this page comes from the IRS page in the list, read on the date shown. Your notice itself is the final word on its own dates and amounts.