CP10 Notice: Changes to Your Estimated Tax Credit Carryover

A CP10 notice means the IRS corrected one or more mistakes on your tax return, and the correction changed the amount you wanted credited to next year's estimated tax. Many self-employed people, retirees and investors choose to leave an overpayment with the IRS as a head start on the next year's tax. When the IRS's correction shrinks that overpayment, less carries forward. If you agree with the change, you don't need to reply. The main thing to do is check your estimated payments for the current year.

Why you got a CP10

On your return you asked the IRS to apply some or all of your overpayment to the following year's estimated tax. While processing the return, the IRS corrected what it considers a mathematical or clerical error. That correction reduced the overpayment, so the amount available to carry forward changed.

Typical errors include:

• Arithmetic mistakes or amounts carried wrongly between lines.
• A credit claimed without the required information, or above its legal limit. The IRS lists Schedule 8812 (Additional Child Tax Credit) among the related references for this notice.
• Payments or withholding that don't match IRS records.

A CP10 is sometimes described as a "less refund than expected" notice, but the IRS's own description focuses on the amount applied to next year. If the change mainly altered a refund paid to you, you would more likely get a CP12.

What the CP10 says

Look for:

• "What we changed on your return", with a short reason for each change.
• The corrected overpayment and how much will be applied to next year's estimated tax.
• Any refund still due to you.
• A date to contact the IRS if you disagree, and the toll-free number under "Where to find more information."

As described in the IRS's internal manual, the tax code gives you 60 days from the date of a math error notice to ask that the change be reversed. Your notice shows the exact date.

What to do

If you agree

No response is required. If a refund is due, the IRS says you should receive it within 4 to 6 weeks, as long as you don't owe other tax or debts it must collect.

If you disagree

Call the toll-free number on the notice by the date shown. The IRS says many return errors are fastest to resolve by phone, and you may be able to fax a missing form during the call. It says it will reverse most changes that reduced the refund you requested, without requiring an explanation, though documents can speed things up. If the IRS does not receive information that supports your original return, it may forward the case to audit, and audit staff should contact you within 6 weeks.

If you need another correction

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

What happens if you ignore it

If you agree, nothing bad happens. The risk is indirect: if you were relying on a larger carryover and don't adjust your current-year estimates, you could end up owing at filing time, possibly with an estimated tax penalty. That could later produce a notice like a CP23 or a balance due.

If you disagree and don't contact the IRS by the date on the notice, you lose the formal right to have the change reversed and to appeal to the U.S. Tax Court. The IRS says it will still consider supporting documents sent later.

Is this notice real?

CP10 is a standard IRS notice sent by mail. To verify it, check your IRS Online Account, which shows payments and credits, or call the IRS at a number listed on irs.gov. The IRS doesn't demand payment by gift card or wire transfer. See how to spot 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.