Form 8812, Additional Child Tax Credit
If you had three or more children and your tax bill is too low to allow you to claim all of your child credit, you must complete and file IRS Form 8812, in order to be able to claim the extra refundable amount.
Form 8812, Additional Child Tax Credit (standard .pdf file)
Form 8812, Additional Child Tax Credit (fill-in .pdf file)
The file is in Adobe portable document format (PDF), which requires the use of Adobe Acrobat Reader.
For more information, see our discussion of claiming the child tax credit.