Do I need to include child support on my federal taxes?

Child support is a financial agreement intended to ensure the needs of minors are met after the parents part ways. Whether you're the payer or receiver of this child support, there is no need to include it on your federal tax return. 

This is because child support is considered to be tax neutral: 

• From the perspective of the receiver, the payments will be used to support the expenses involved with raising a child. This is essentially the same thing as if the parents were still together and paying for these costs out of pocket. 
• From the perspective of the payer, the payments are made using after-tax money to support the well-being of your children. Again, this is essentially the same thing as if you had your child full-time and paid for their expenses like normal. Therefore, since the IRS sees this as a personal expense, there is no applicable tax deduction.

One exception is when calculating your gross income to see if you're required to file a federal tax return. In this case, any child support payments you've received may be subtracted (source).

Child and Dependent Care Tax Credit 

While child support payments may not be tax deductible, there is a possibility that you may qualify to claim the Child and Dependent Care Tax Credit. When calculating your income to see if you’re eligible, you may exclude any child support payments you've made this year.

Note that only one parent may claim a child for the tax year. Therefore, there will need to be an agreement ahead of time as to who gets to include your child on their tax return and apply for the child tax credit.  

For more information, please check IRS Publication 504, Divorced or Separated Individuals.