How Pennsylvania calculates child support
Pennsylvania uses the income shares model. The guideline starts from the idea that children should receive the share of income they would have had if the parents lived together, and it splits that amount between the parents according to what each one earns. The rules are the Pennsylvania Rules of Civil Procedure 1910.16-1 through 1910.16-7. The schedule and the self-support reserve used here took effect on January 1, 2026.
Start with each parent's net income
Pennsylvania works from monthly net income. Gross income includes wages, bonuses, commissions, net business income, interest, rents, royalties, dividends, pensions, unemployment and disability benefits, and most other money received. Public assistance and SSI do not count. From gross income the rule subtracts income taxes, Social Security and Medicare (or self-employment tax), non-voluntary retirement payments, mandatory union dues and alimony paid to the other party (Rule 1910.16-2). The calculator asks for the result, so enter each parent's net figure.
Look up the basic obligation
The two net incomes are added. The Basic Child Support Schedule (Rule 1910.16-3) lists an amount for each combined income from $1,300 to $30,000 a month, in steps of $50, for one to six children. The rule does not say what to do between two rows, and its worked examples all use incomes that fall exactly on a row. The calculator uses the nearest row; that is a convention of this calculator, not an instruction in the rule.
Above $30,000 of combined net income, the schedule is extended by a percentage of the excess, from 4% of the extra income for one child to 6.3% for six (Rule 1910.16-3.1). The rule then asks the court to consider the children's reasonable needs, and it may adjust the result up or down, but not below the amount at $30,000. That last step is a judgment, so the calculator shows only the starting figure.
Split it by income
Each parent's percentage of combined net income is his or her share. The rule's own examples round that percentage to a whole number (53%, not 52.6%) and then round the dollar result, and the calculator follows them. The parent with fewer overnights normally pays that share to the other parent.
Adjust for time with the children
If the paying parent has the children 40% or more of the year's overnights, the rule presumes a reduction (Rule 1910.16-4(c)). The calculator checks the threshold on the exact share of the year, so 146 of 365 overnights qualifies and 145 (39.7%) does not. The paying parent's percentage share is lowered by the time percentage minus 30 points, so 40% of the time cuts the share by 10 points, and 50% cuts it by 20. With exactly equal overnights, the parent with the higher net income is the payer, a lower earner never pays basic support to a higher earner, and if the calculation would leave the recipient with a larger share of the parents' combined net income than the payer, basic support is reduced until the combined net income is split equally (Rule 1910.16-4(c)(2)(iv)). Child care, insurance and other additional expenses are shared separately. A 365-day year cannot be split exactly in half, so the calculator treats 182 or 183 overnights as equal time; the rule does not address that. A lower earner can still owe a share of child care or insurance, and when that share is larger than the basic support owed, the calculator shows the net amount running the other way. The presumption can be rebutted.
The self-support reserve
The schedule is built around a self-support reserve of $1,255 a month. When the paying parent's income falls in the shaded low-income area of the schedule, support is the lower of the normal result and the amount found by looking up the paying parent's income alone (Rule 1910.16-2(e)). The plain text of the rule does not mark which cells are shaded, so the calculator reads the shaded area from the schedule figures that follow the reserve formula; near the edge of that area the printed schedule should be checked. If that parent's net income is at or below the reserve, the rule says support is set only after the court considers actual resources and living expenses, so the calculator shows no guideline figure for basic support there. Child care and insurance can still be divided between the parents, and the calculator shows that share separately.
Add child care and health insurance
Child care needed to work or study and health insurance premiums are added, divided between the parents in proportion to net income (Rule 1910.16-6). Child care is first reduced by the federal child and dependent care credit available to the eligible parent, whether or not it is claimed, and is not reduced if that parent does not qualify. The calculator does not compute the credit, so it asks for child care after the credit. The premium shared includes the part for the children, a premium a step-parent in the household pays for the children, and the part for a party or other person the payer has a legal duty to support; coverage for anyone else is left out. When the paying parent pays the insurance, the other party has no or minimal income and the paying parent will bear 90% or more of the premium, the court may instead deduct part or all of the premium from the paying parent's gross income, and the premium is then not divided as well (Rule 1910.16-6(b)(4)). Unreimbursed medical costs above $250 per person a year are also shared by income, but they are not part of the monthly figure.
What the calculator leaves out
It covers one set of children and does not model split custody, support for children in other households, a child's Social Security benefit, imputed income, or the spousal support formulas. A court can depart from the guideline for reasons listed in Rule 1910.16-5, and a parent with a new family can ask for a reduction under Rule 1910.16-7.