If your available Child Tax Credit is greater than your tax liability, the Child Tax Credit can only reduce your tax bill to zero — you don’t get any unused portion of the credit back as a refund. However, you may be able to claim the Additional Child Tax Credit
To claim the Additional Child Tax Credit you must have a minimum of $2,500 of earned income to claim the ACTC. Earned income can come from salaries and wages, self-employment, and some disability payments.
Form 8812 is used to calculate your Additional Child Tax Credit. TurboTax will ask you a few simple questions about your dependents and income, calculate your credit, and fill in all of the right forms for you.