To claim the child tax credit, you must file Form 1040 or Form 1040A. You cannot claim the child tax credit on Form 1040EZ. You must provide the name and identification number (usually a social security number) on your tax return for each qualifying child.
If you are filing Form 1040 answer the Questions in your form instructions for line 51, Form 1040, to find out which child tax credit worksheet you can use to figure the credit.
If you answer "Yes" to question 1 or 2 in your Form 1040 instructions, you must complete the child tax credit worksheet in Publication 972. Otherwise, you can use the Child Tax Credit Worksheet in your Form 1040 or Form 1040A instructions. (See the filled-in example