Claiming infant child

What is the name of your state? MD

My son's father and I were never married so I know that in order to claim the baby we have to prove who provided 50% support or more.

Here is my question though. My son was a little over 4 months old at the end of the year and we both lived with my ex for 2 months and then I moved out and for the other 2 months he lived exclusively with me. I looked at the worksheet that the IRS provides to figure out who provided more support. For shelter do you figure in only when the child was in the home or for the whole year since you are claiming the child for 12 months even though they were born late in the year?

I figured I paid for more than 50% support and claimed him as my dependant but now his father says that he is going to claim him also. Now I'm figuring we will be getting audited.

Another question that I'm kind of confused about. If I didn't claim my son would I still be able to be eligible for EIC? From the IRS website it seemed like they were saying that even if you didn't claim your child as a dependant you could still receive the EIC.

You get him for EIC. As for the dependency, who paid for the diapers? health insurance? food? clothes? crib? day care? the house he lived in? Compare the amount you contributed to the household while living with dad, and 1/2 (assuming only 1 child) of what you spent to live in a separate apt as your housing expenses. Add in other expenses, and compare this with what dad spent & paid in child support.