Almost every state uses one of three formulas. Knowing which one your state uses tells you what information matters most. We explain the model and the factors — we don't estimate a dollar amount, because the real number comes from your state's official worksheet and a judge's review.
Income Shares model
Both parents' incomes are combined to estimate what they would have spent on the child if the family were intact, then each parent pays a share in proportion to their income. Used by most states.
Percentage of Income model
Support is set as a percentage of the paying parent's income, scaled to the number of children. The custodial parent's income is generally not part of the base calculation.
Melson Formula
A more detailed formula that first sets aside each parent's own basic self-support needs, then divides the remaining income to cover the child's needs plus a share of any surplus. Used by only a few states.
General reference only, last reviewed 2026-06. This tool explains the method, not your exact amount. LexPilot is an independent information directory. It is not a law firm, does not provide legal advice, and does not create an attorney–client relationship. Always consult a licensed attorney for advice on your specific situation.