The child tax credit is a $2,000 (just for 2021 it is $3,600 for a child 5 years or younger and $3,000 for children between the ages of 6 and 17.) tax credit for each qualifying dependent child claimed on your return.
To qualify, your child must meetallof these requirements:
Be under age 17 at the end of the tax year
Is your child, stepchild, foster child, adopted child, sibling, step sibling, half sibling, or a descendant of any of them (for example, a grandchild, niece, or nephew)