Benefits that actually belong to the child because of your early disability of a parent will not be included in your tax return. You should consider only your benefits when figuring out how much tax to have withheld.
You can have 7%, 10%, 15% or 25% of your monthly benefit withheld for taxes. If you believe part of your social security benefits will be taxed because your other income plus half of your social security benefits will exceed $25,000 ($32,000 for married filing jointly) then you can decide a minimum withholding percentage of 7%.
Consider that the maximum amount of your benefits that can be taxed is 85% when making your decision.
