US State Child Support Guidelines, Models & Statutory Frameworks

California calculates statutory child support using a precise algebraic formula: CS = K[HN - (H%)(TN)]. Support is determined by parents’ net disposable incomes, the higher earner’s percentage of physical custody (H%), and statutory multi-child multipliers.

Massachusetts applies an Income Shares Model that calculates child support based on the combined gross incomes of both parents and the number of children. In shared physical custody (121 to 183 overnights, or 33% to 50%), the court applies a reciprocal offset calculation.

New York calculates child support under the Child Support Standards Act (CSSA). Combined parental income is multiplied by a statutory child percentage (17% to 35%) up to the statutory cap ($183,000/yr), and apportioned between parents based on their pro-rata income shares.

Texas bases child support exclusively on the paying parent’s (Obligor’s) Net Resources. The custodial parent’s income is not factored into the basic guideline calculation. Net resources are subject to a statutory monthly cap of $9,200.

Florida calculates child support under an Income Shares Model based on combined net monthly incomes. When a parent exercises substantial time-sharing of 20% or more (at least 73 overnights per year), Florida law mandates the 1.5x Gross-Up Method pursuant to Fla. Stat. § 61.30(11)(b) to account for duplicated household expenditures.

Pennsylvania calculates child support under an Income Shares Model based on combined monthly net parental incomes. Under Pa. R. Civ. P. 1910.16-4(c), when an obligor exercises 40% or more parenting time (at least 146 overnights per year), the guideline support obligation is reduced based on time exceeding 30%, with equal 50/50 custody calculated as a direct reciprocal net offset.

Illinois calculates child support under the Income Shares Model pursuant to 750 ILCS 5/505 based on combined net monthly parental incomes. When each parent exercises at least 146 overnights per year (40%), Illinois applies the Shared Physical Care formula under § 505(a)(3.8), multiplying the basic support obligation by 1.5 and cross-allocating by respective overnight percentages.

Ohio calculates child support pursuant to Ohio Revised Code § 3119.01 using the Income Shares Model. Under R.C. § 3119.051, when a parent exercises court-ordered parenting time equal to or exceeding 90 overnights per year, the court must reduce that parent’s annual child support obligation by an automatic 10% statutory credit. If parenting time reaches 147+ overnights, courts may award additional deviations.

Georgia calculates child support pursuant to O.C.G.A. § 19-6-15 under the Income Shares Model. Gross parental incomes determine the Combined Adjusted Gross Income (AGI), which corresponds to the Basic Child Support Obligation (BCSO) table. Each parent is allocated a pro-rata share, with credits applied for health insurance and adjustments for shared parenting time.

North Carolina calculates child support under N.C. Gen. Stat. § 50-13.4 using the Income Shares Model. The state utilizes Worksheet A (Form AOC-CV-627) for primary custody and Worksheet B (Form AOC-CV-628) for shared physical custody when both parents exercise at least 123 overnights per year (~33.7%). Worksheet B applies a 1.5x basic obligation multiplier to reflect dual household overhead.

Michigan calculates child support under MCL § 552.605 using the Michigan Child Support Formula (MCSF). The formula utilizes net monthly parental incomes and applies a continuous exponential Parental Time Offset equation: Pt = (Ts^3 * Ot) / (Ts^3 + To^3). This mathematical curve eliminates arbitrary cliff thresholds by adjusting support continuously according to the exact number of annual overnights.

New Jersey calculates child support under Court Rule 5:6A and Appendix IX using the Income Shares Model. Appendix IX-C (Sole-Parenting Worksheet) applies when the Parent of Alternate Residence (PAR) has under 104 overnights. Appendix IX-D (Shared-Parenting Worksheet) applies when the PAR exercises 104 or more overnights (28%), decomposing child expenditures into fixed (38%), variable (37%), and controlled (25% PPR) components.

Virginia calculates child support under Va. Code Ann. § 20-108.2 using the Income Shares Model. Under § 20-108.2(G)(3), shared custody applies when each parent has physical custody of a child for more than 90 days (overnights) in a year. When triggered, the basic support obligation is multiplied by 1.4 (140%) to cover duplicated household expenses and cross-allocated by respective custody percentages.

Delaware is the birthplace and canonical reference of the Melson Formula, codified in Family Court Civil Rule 501. The formula operates on three fundamental statutory tiers: (1) each parent retains a Self-Support Allowance ($1,350/mo), (2) remaining net income is pooled to cover Primary Child Support Needs ($600 for 1st child, $350 for each additional child), and (3) children share in parental prosperity through a Standard of Living Adjustment (SOLA) percentage applied to discretionary surplus income.