Child support calculations follow state-specific formulas designed to produce consistent, predictable support amounts based on parental income and family circumstances. Understanding how your state determines support helps you anticipate obligations, evaluate whether existing orders are accurate, and prepare for modification proceedings.
Income Shares vs. Percentage Models
Most states use income shares models that estimate total child-rearing costs based on combined parental income, then allocate those costs proportionally based on each parent's income share. If one parent earns 60% of combined income, they bear 60% of calculated costs. The non-custodial parent's share becomes the support payment, as the custodial parent is presumed to spend their share directly on the child.
Percentage models used by some states apply a fixed percentage to the non-custodial parent's income rather than calculating total costs. The percentage may vary by number of children but doesn't consider the custodial parent's income. This simpler approach produces different results than income shares when parental incomes differ substantially.
Determining Parental Income
Gross income forms the starting point for most calculations, including all earnings from employment, self-employment, investments, and other sources. Courts examine tax returns, pay stubs, and financial documents to determine actual income. When income is variable or concealed, averaging over periods or imputing income based on earning capacity may be necessary.
Self-employed parents present calculation challenges because business expenses reduce reported income and may be manipulated. Courts scrutinize self-employment deductions carefully and may add back expenses that benefit the owner personally. Business revenues rather than profits may be considered when expense claims seem excessive.
Adjustments to Basic Calculations
After calculating basic support from income tables, various adjustments apply. Health insurance premiums for children are typically added to base support. Work-related childcare expenses may be shared proportionally. Extraordinary educational or medical expenses can warrant additional support beyond standard calculations.
Parenting time adjustments reduce support when non-custodial parents have children for substantial periods. The theory is that these parents directly cover children's costs during their time, reducing the custodial parent's expenses. Thresholds vary by state, with adjustments typically beginning when non-custodial time exceeds specified percentages.
Multiple Family Situations
When parents have support obligations to children from multiple relationships, adjustments account for these competing duties. Prior support orders may be deducted from income before calculating new obligations. Children living with the paying parent may reduce available income for support. These adjustments prevent ordering support that ignores other legitimate family obligations.
New families don't eliminate existing obligations. Having additional children with new partners doesn't automatically reduce support for prior children. However, changed financial circumstances from supporting additional dependents may support modification requests in some jurisdictions.
Deviations from Guidelines
While guideline calculations create presumptive support amounts, courts can deviate when guideline amounts would be inappropriate. High-income parents may face caps preventing support far exceeding actual child costs. Special needs children may warrant enhanced support. Unusual circumstances justifying deviation must be documented, as courts generally follow guidelines absent compelling reasons to deviate.