VALID › Notice Library › CP12 notice (including CP12, CP12E, CP12F, CP12G, CP12N, and CP12U)
In the IRS’s own words · not reviewed by VALID
CP12 notice explained, in the IRS’s own words
We corrected one or more mistakes on your tax return. As a result, you are now either due a refund or your original refund amount has changed.
Read the full CP12 page on irs.gov ↗
What this notice is about
We corrected one or more mistakes on your tax return. As a result, you are now either due a refund or your original refund amount has changed.
What you need to do
Read your notice carefully to see what was changed on your return and how those changes affected your refund.
If you agree with the changes we made, no response is required.
- You should receive a refund check in 4-6 weeks, as long as you don't owe other tax or debts we're required to collect. Check on the status of your refund.
- You may want to correct the copy of your tax return that you kept for your records, but do not send it to us.
If you disagree with our changes, contact us at the number shown on the notice by the date indicated.
You may want to
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- Access tax records
- View your balance
- Make and view payments
- View or create payment plans
- Manage your profile preferences
- View tax professional authorizations
- Learn more about accessibility options
- View tax transcripts
Frequently asked questions
Why did I receive this notice? (updated Nov. 3, 2025)
We issue a CP12 when we correct one or more mistakes on your tax return, and:
The refund is different from the one you expected, or
You have a refund when you thought you owed money or had an even balance.
How can I find out what caused my tax return to change? (updated Jan. 3, 2025)
Review the “What we changed on your return” section of your notice. For more information about the errors on your return, call us at the number shown in the “Where to find more information” section of your notice.
What should I do if I disagree with the changes you made? (updated Nov. 3, 2025)
- If you disagree, contact us by the date shown on your notice. Call us at the toll-free number shown in the “Where to find more information” section of your notice. The fastest way to resolve many return errors is by telephone. Some cases require additional information that you may provide verbally. If we need a missing or corrected form or document, you can fax your documents using either a fax machine or online fax service while on the telephone. Protect yourself when sending digital data by understanding the fax service’s privacy and security policies.
We'll reverse most changes we made if we reduced the refund you requested on your return. You don't need to provide an explanation or additional documents when you request the reversal, but doing so may help us resolve your case more quickly. If we don't receive information that supports your original return, we may forward your case for audit, in which case the audit staff will contact you within 6 weeks to explain the process and your rights.
If you don't contact us by the date shown on your notice, you will lose formal rights to have the change(s) reversed, as well as your right to appeal our decision to the U.S. Tax Court. However, if you contact us and send supporting documentation after that date, we will consider that information and we may reverse the change(s) to your return if we agree with you.
Tips for next year
Consider filing your taxes electronically. Filing online can help you avoid mistakes and find credits and deductions that you may qualify for. In many cases you can file for free.
To avoid the same issue next year, correct the copy of this year's tax return that you kept for your records. If you use a tax preparer, also have them correct their copy.
What to do next
- Write down the date on the letter today.
- Look the number up on irs.gov yourself. Don’t trust a link or phone number from anyone else.
- If it says you owe money or proposes changes to your return, take it to a licensed CPA, EA or tax attorney before that date.
Not advice. Not a filing. Verify with a licensed professional. Rules change by year and facts.
Run a tax firm?
Notice Desk drafts the CP12 client email, the response letter and the deadline, citing the law, for your licensed staff to review and sign.