Can I claim a newborn baby?
You can claim a child born anytime in 2018 on your 2018 taxes, assuming they meet all the other dependent qualifications. A baby born in 2019 can be claimed on your 2019 taxes.
When we ask how many months your newborn lived with you, always answer The whole year, even if your baby was born on the last day of 2018. The same holds true for any health care coverage questions if your newborn was insured from the date of birth.