The three types of tax credits are refundable, nonrefundable, and partially refundable. Refundable tax credits are the most valuable, since they refund you the difference if the credit exceeds your tax bill. Nonrefundable tax credits can reduce your tax bill to $0, but they don’t offer a refund after that. Partially refundable credits can offer a refund after your tax liability goes down to zero. Still, the amount will vary and won’t add up to the maximum amount of the credit.