Rule 502.Net available income

The shape of it. Net available income is gross income minus limited deductions and a self support allowance, then discounted by a percentage reflecting the other children a parent must support. Everything is monthly and rounded to the nearest whole number.

Gross income. Salary and wages, including commissions, bonuses, overtime and anything else subject to federal retirement or Medicare taxes — and for support purposes, everything an employer labels pre-tax. Self-employment income subject to federal self-employment tax. Unearned taxable income: dividends, severance, pensions, interest, trust income, annuities, capital gains, workers' compensation, unemployment compensation, disability insurance benefits, prizes, and alimony received.

Counting pre-tax benefits is deliberate. Money routed around a paycheque is still money.

Nontaxable income. Most Social Security disability or retirement benefits and some private disability pensions count. Benefits paid to a child because of a parent's disability are income to that parent but offset their net monthly obligation dollar for dollar — so the child's money reduces the bill rather than inflating it. Need-based benefits paid to a child for the child's own disability, such as Supplemental Security Income, are income to neither parent.

Military allowances count as income, except clothing allowances; a servicemember's housing allowance is capped at what they would receive if stationed at Dover Air Force Base, so a posting to an expensive city does not inflate their support figure.

What is not income. Expense reimbursements and in-kind payments received in employment count only if significant and only if they reduce personal living expenses. A cost-of-living stipend for relocating to an expensive place is excluded if clearly identified on pay documents. Adoption subsidies are excluded.

Taxes. Taxes are not deducted, actual or estimated — with one exception. A self-employed parent who documents actual payment of self-employment taxes has income reduced by 7% of self-employment income, to the extent wages plus self-employment income stay within the Social Security wage base. That is the employer's half of the payroll tax, which an employed parent never sees.

Deductions. Medical insurance premiums, including COBRA, paid by either parent regardless of who is covered — unless the policy also covers the children of the union, in which case it is handled as primary support instead. All mandatory retirement contributions; and where those come to less than 5% of gross income, voluntary contributions to a qualifying plan up to 5% including the mandatory part. Union dues required as a condition of employment. Court-ordered alimony paid. Disability insurance premiums for income replacement — but not policies that merely guarantee a credit card or mortgage. Other mandatory unreimbursed business expenses, such as supplies the employer requires.

The list is short by design. A support formula that deducted every expense would produce whatever answer the better-documented parent wanted.

The self support allowance. 120% of the federal poverty guideline for a one-person household, rounded to the nearest $10 and adjusted each January. This is the money a parent keeps before any support is calculated — the recognition that a parent who cannot house and feed themselves will not be paying support for long.

Other children. A parent with other dependent children, in or out of the household but not step-children, has their income after the allowance multiplied by 70%. Children outside the household count only where there is a support order or proof of a pattern of support. Support of an adult dependent may be recognised similarly, but only where the parent is legally obliged to provide it.

The dilution is flat rather than headcount-based, and it does not let a parent reduce this child's support by asserting obligations they do not actually meet.