IRS CP12: what it means and what to do

• The IRS corrected mistakes on your return and your refund differs from what you expected
• You are getting a refund when you thought you owed or expected to break even

1. Review the What we changed on your return section of the notice
2. If you agree, no response is required; expect your refund in 4-6 weeks unless you owe other taxes or debts
3. Correct your own copy of the return but don't send it to the IRS
4. If you disagree, contact the IRS at the number on the notice by the date indicated

Deadline: By the date shown on your notice

Call the toll-free number in the Where to find more information section of the notice; you can fax missing or corrected forms during the call. Most changes that reduced your refund are reversed on request. If support for your original return isn't received, the case may be sent for audit, and audit staff would contact you within 6 weeks.

If you disagree but don't respond by the deadline, you lose your formal rights to have the changes reversed and to appeal to the U.S. Tax Court. Documents sent later will still be considered and changes may be reversed if the IRS agrees.

Most notices come down to matching what the IRS has on file against your own records. Before you reply, pull the return the notice refers to, the bank statements and income forms for that year, and any payment confirmations. If your books are reconciled to the bank, that comparison takes minutes instead of days.

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IRS: Understanding your CP12 notice (including CP12, CP12E, CP12F, CP12G, CP12N, and CP12U) →

Last verified against that page on October 13, 2026. This is general information, not advice for your situation. The notice itself is the authority on your amounts and dates. Talk to a CPA or enrolled agent if the amounts are large or you are unsure.

• All IRS notices explained
• IRS CP2000 — The IRS is proposing changes to your tax return because income or payment information it received from third parties does not match what you reported.
• IRS CP14 — The IRS says you owe money on unpaid taxes.
• IRS CP501 — This is a reminder that you still owe a balance on one of your tax accounts.
• IRS CP503 — This is your second reminder that you have an unpaid balance on one of your tax accounts, because the IRS hasn't received your payment or a response to earlier notices.
• IRS CP504 — This is a Notice of Intent to Levy under Internal Revenue Code section 6331(d) and a final reminder that the IRS may levy your wages, bank accounts, or state tax refund for an unpaid balance.
• IRS LT11 — The IRS has not received payment for overdue taxes and intends to seize your property or rights to property.
• Find an accountant — for help responding.