California runs a strict income shares system under the statewide uniform guideline, and parents who stipulate below guideline must satisfy Family Code section 4065: they are fully informed, no one was coerced, and the deal serves the child. Agreements are filed on form FL-350, with an Income Withholding Order (FL-195) if wages are garnished, and the local child support agency must sign when it is part of the case. A parent on public assistance generally cannot sign away support. The waiver of guideline support, where allowed, has to be in writing to bind either side.
Texas uses a percentage of income model that applies a set percentage of the obligor's net resources, twenty percent for one child rising with each additional child, capped at a statutory net-resources ceiling that the Office of the Attorney General adjusts periodically. Texas courts can order support past eighteen for a child still in high school, and medical and dental support are mandatory add-ons. Agreed orders are common, but the court still confirms the percentage math before signing.
Florida follows income shares under Florida Statutes section 61.30, with a guideline schedule keyed to combined net income and a built-in adjustment when a parent exercises at least twenty percent of overnights. The statute requires both parents to file financial affidavits, and a court will not rubber-stamp a number that departs from the worksheet by more than five percent without written reasons. Health insurance and childcare are added before the obligation is prorated.
New York applies the Child Support Standards Act, a percentage model taking seventeen percent of combined parental income for one child and scaling up to thirty-one percent for five or more, applied up to a periodically adjusted income cap. Add-ons for childcare, health, and education are prorated separately. Parents can opt out of the formula in a written agreement, but the agreement must recite the guideline amount and explain the deviation, or a court will set it aside.