How to Fill Out IRS Form 15110: CP08 Response With Schedule 8812

To fill out IRS Form 15110, the Additional Child Tax Credit Worksheet, enter your contact information at the top, then work across the eligibility table row by row for each dependent child already listed on your 2025 return, marking whether the child meets every qualifying factor printed on the form. Total the children who qualify, attach a completed Schedule 8812, and send both back to the IRS within 30 days of the date on your CP08 notice.1Internal Revenue Service. Understanding Your CP08 Notice

What Form 15110 Is and Why the IRS Sent It

The CP08 notice goes out when IRS records show you have a dependent who looks like a qualifying child, but you didn’t claim the Additional Child Tax Credit (ACTC) on your return. It’s not an audit. It’s the IRS pointing to a refund you may be owed and asking you to confirm eligibility on the worksheet.

For 2025, the refundable ACTC is worth up to $1,700 per qualifying child if you have at least $2,500 in earned income.2Internal Revenue Service. Child Tax Credit Form 15110 itself does no math. It’s a one-page eligibility check. The dollar figures come out of Schedule 8812, which travels with it.

Fill In the Contact Section

At the top of the worksheet, enter your name, Social Security number, mailing address, and a daytime phone number. If you filed jointly, add your spouse’s name and Social Security number. The form asks for a preferred time to call, so give a window when you can actually pick up. The IRS may call to clarify something before releasing the credit.

Complete the Child Eligibility Table

The middle of the form is a table. For each dependent child from your original 2025 return, enter the child’s name and Social Security number, then answer Yes or No to whether the child meets every one of the qualifying-child factors the form lists. A single No on any factor disqualifies that child. At the bottom of the table, write the total number of children who qualify.

For 2025, a qualifying child must:

  • Be under 17 at the end of the year.
  • Be your son, daughter, stepchild, adopted child, eligible foster child, sibling, step-sibling, half-sibling, or a descendant of any of these (such as a grandchild, niece, or nephew).
  • Not have provided more than half of their own financial support during the year.
  • Have lived with you for more than half the year.
  • Be claimed as a dependent on your return.
  • Not file a joint return for the year, unless filing only to claim a refund of withheld or estimated taxes.
  • Be a U.S. citizen, U.S. national, or U.S. resident alien.
  • Be younger than you (or your spouse, if filing jointly), or be permanently and totally disabled.

Each qualifying child also needs a Social Security number valid for employment, issued before the due date of your return including extensions.2Internal Revenue Service. Child Tax Credit An ITIN doesn’t count.

If you have more qualifying children than the form has rows, list the extras (name, Social Security number, and eligibility answers) on a plain sheet and attach it.3Internal Revenue Service. Form 15110 – Additional Child Tax Credit Worksheet

You Cannot Add a Child Who Wasn’t on Your Original Return

Form 15110 only works for children the IRS already sees on your filed Form 1040. If you left a qualifying child off entirely, don’t try to add them here. File Form 1040-X instead.3Internal Revenue Service. Form 15110 – Additional Child Tax Credit Worksheet

Attach a Completed Schedule 8812

If at least one child qualifies on the worksheet, the IRS requires you to send Schedule 8812 (Credits for Qualifying Children and Other Dependents) with it. That’s where the credit is actually calculated.1Internal Revenue Service. Understanding Your CP08 Notice

Have these numbers ready from your 2025 return: adjusted gross income, total tax liability, and earned income. The ACTC equals 15% of your earned income above $2,500, capped at $1,700 per qualifying child for 2025.4Office of the Law Revision Counsel. 26 USC 24 – Child Tax Credit The credit phases out at $50 per $1,000 once modified adjusted gross income exceeds $200,000, or $400,000 for married filing jointly.5Internal Revenue Service. Instructions for Schedule 8812 (Form 1040) (2025)

Schedule 8812 and its line-by-line instructions are on irs.gov. Work through the parts carefully; the schedule handles both the nonrefundable Child Tax Credit and the refundable ACTC, and it’s easy to mix up which lines apply.

Send Both Forms Back Within 30 Days

Your CP08 notice gives you 30 days from the notice date to respond.1Internal Revenue Service. Understanding Your CP08 Notice You have two ways to submit:

  • Online upload. Go to the IRS Document Upload Tool at apps.irs.gov/app/digital-mailroom/notices and enter the access code printed on your notice. This is the faster route.
  • Mail. Use the envelope that came with the notice. If it’s gone, mail to the address in the top-left corner of the CP08 itself. Sending it elsewhere can delay processing.1Internal Revenue Service. Understanding Your CP08 Notice

Send Form 15110 and Schedule 8812 together. One without the other slows the review.

What to Expect After You Send It

The IRS reviews the packet and either approves the credit and issues the refund, or sends a letter explaining a denial and your next steps.1Internal Revenue Service. Understanding Your CP08 Notice No fixed timeline is published, so give it several weeks, longer during peak filing season.