Social Security survivor benefits for children are considered taxable income only for the children who are entitled to receive them, even if the checks are made out to a parent or guardian. Most children do not make enough in a year to owe any taxes.
However, survivor benefits are taxed if half of the child's benefits in a year, added to any other income the child earns in the year, is enough to require him or her to file a tax return and pay taxes. If half of the annual benefits plus the child's other income exceeds a base amount determined by the IRS ($25,000 in 2018), then a portion of the benefits is taxable.
Most checks for Social Security survivor benefits are made out to an adult, such as a parent, on the child's behalf. The amount of the benefits does not affect the income tax of the parent. If both the parent and the child receive benefits, the amount designated for the eligible child is subtracted from the check to determine the parent's tax liability. The child receiving the benefits may still be considered a dependent for tax purposes if he or she lives with the parent for more than half the year and the parent pays for more than half of his or her living expenses, such as food, housing, clothing, education and medical care.
Social Security benefits are reported to the IRS. The recipient of the benefits receives an SSA-1099 form in January, including amounts of all benefits received during the previous year.
For background, see Social Security Benefits for Children: How They Work.