It's not whether you get a refund or tax due. And the withholding doesn't matter. It's if you have a tax liability on your income. Look at your 1040 line 22 for total tax. The credit can only reduce the tax to zero. If your non-refundable credits reduce your tax to 0 you will get back all the withholding and payments and any Refundable Credits. Unless you owe for something else like self employment tax or the 10% Early Withdrawal Penalty on IRA withdrawals.
