The payment or receipt of child support does not affect your taxable income. You should not report child support payments in your income.
If you make child support payments, you cannot deduct the amount you paid. If you receive child support payments, the amount you receive is not taxed. Do not report this amount on IRS Form 1040, Line 21 Other Income.
Child support is defined as payment that is specifically designated as child support or treated as specifically designated as child support under your divorce or separation instrument. The amount of child support may vary over time.
Child support is not considered alimony for tax purposes. Unlike child support payments, alimony is deductible by the payer and must be included in the spouse's or former spouse's income.
Underpayment. If both alimony and child support payments are called for by your divorce or separation instrument, and you pay less than the total required, the payments apply first to child support and then to alimony.
For more information on child support, see IRS Publication 504 Divorced or Separated Individuals.