Is the child tax credit a refundable credit?

It can be. The Child Tax Credit is 2 parts. The first is non-refundable and can only reduce the tax to $0. If the full amount of the credit (generally $1000 a qualifying child) is not used, it becomes the Additional Child Tax Credit and the amount of refundable credit is calculated on Form 8812. The amount that can be refundable will depend on the wages and other income on the return.