CP12 Notice: IRS Changed Your Return and Your Refund

A CP12 notice means the IRS corrected one or more mistakes on your tax return while processing it, and the correction changed your refund. Sometimes the refund is smaller than you claimed. Sometimes it is larger, or you are due money when you thought you owed. Either way, no one audited your return; this is an automatic correction. If you agree with it, you do not need to do anything.

Why you got a CP12

The IRS can correct certain mathematical or clerical errors without an audit. The IRS sends a CP12 when it makes such a correction and either:

• Your refund is different from the one you expected, or
• You now have a refund when you thought you owed money or had a zero balance.

Common causes include arithmetic mistakes, an amount copied wrongly between lines or schedules, a credit claimed without required information (such as a valid Social Security number), a credit above its legal limit, or withholding and estimated payments that do not match IRS records.

There are several versions of this notice (CP12E, CP12F, CP12G, CP12N and CP12U, among others). They work the same way.

What the CP12 says

Look for:

• "What we changed on your return": each correction, briefly explained.
• Your corrected refund or overpayment amount.
• A contact-by date, if you disagree.
• "Where to find more information": the toll-free number.

Under the tax code, as described in the IRS's internal manual, you have 60 days from the date of a math error notice to ask that the change be reversed. The notice prints the exact date.

A quick way to check the notice: put your copy of the return next to it and find each line the IRS mentions. Most changes trace back to one or two entries, such as a credit, a withholding amount from a W-2, or an estimated payment. Knowing exactly which line changed makes any phone call much shorter.

What to do

If you agree

No response is needed. The IRS says you should receive the refund in about 4 to 6 weeks, as long as you don't owe other tax or debts the IRS is required to collect. If part of the refund is used to pay a past-due tax, you would get a separate notice such as a CP49. Debts like past-due child support or certain federal debts can also reduce a refund through the Treasury Offset Program; see our guide to refund delays and offsets.

If you disagree

Call the toll-free number in the "Where to find more information" section by the date shown. The IRS says the phone is the fastest way to fix many return errors, and you may be able to fax a missing or corrected form during the call.

The IRS says it will reverse most changes that reduced the refund you requested. You don't need to explain or send documents, but doing so can speed things up. If the IRS doesn't receive information that supports your original return, it may send the case to audit, and audit staff should contact you within 6 weeks.

If you need another correction

To fix a different error on the same return, file Form 1040-X. See our amended return guide.

What happens if you ignore it

If you agree, ignoring it is fine; the refund simply arrives. If you disagree and don't call by the date on the notice, you lose the formal right to have the change reversed and the right to appeal to the U.S. Tax Court. The IRS says it will still consider supporting documents sent later and may reverse the change if it agrees. For older, closed issues, audit reconsideration may also be an option.

Is this notice real?

CP12 is a standard IRS mailing. To check it, look at your IRS Online Account or call the IRS using a number from irs.gov. Be wary of any message asking for bank details to "release" a refund, or for a fee by gift card. See our guide to IRS scams.

IRSV.com is an independent guide and is not affiliated with the IRS. This page is general information, not tax or legal advice. Rules change; confirm details on IRS.gov or with a tax professional. Found an error? Tell us.