How is Child Support Calculated in Pennsylvania?

Pennsylvania calculates child support using both parents' net incomes under the Income Shares Model in Pa.R.C.P. 1910.16. Both parents' monthly net incomes are combined, looked up on the Basic Child Support Schedule, and each parent pays their proportional share. Effective January 1, 2026, Pennsylvania updated its guidelines — basic obligations increased 3% to 10% across all income levels, and the self-support reserve rose to $1,255 per month. Pennsylvania also has one of the most detailed shared custody formulas in the country, with specific adjustments at 40%, 45%, and 50% custody time.

How Pennsylvania calculates net income

Unlike Ohio — which uses gross income — Pennsylvania starts with gross income and then subtracts a defined list of deductions to arrive at each parent's monthly net income under Rule 1910.16-2. This net income figure is what feeds the support schedule.

Pennsylvania defines gross income broadly. Wages, salary, bonuses, commissions, self-employment income, rental income, pensions, Social Security disability, and workers' compensation all count. Welfare benefits and Supplemental Security Income (SSI) are excluded.

Pennsylvania's deduction list is exclusive — only these specific items are allowed. Health insurance, voluntary retirement contributions, and personal expenses are not deducted. If a parent has additional income from a side business or investment, that income is included in gross income before these deductions are applied.

If a parent is voluntarily unemployed or working below their earning capacity, Pennsylvania courts may impute income based on what that parent could reasonably earn given their education, experience, and the local job market.

How the Basic Child Support Schedule works

Once each parent's net income is calculated, the two figures are combined. That combined monthly net income is then matched to Pennsylvania's Basic Child Support Schedule under Rule 1910.16-3, which shows the baseline monthly obligation for one through six children at each income level.

The schedule covers combined monthly net incomes from $1,300 up to $30,000. Above $30,000 combined monthly net income, Pennsylvania applies additional percentages to the income above the cap — ranging from 4.0% for one child up to 6.3% for larger families.

Each parent pays their proportional share of the scheduled amount. If Parent A earns 65% of the combined net income, Parent A is responsible for 65% of the basic support obligation.

Worked Example — Two incomes, two children

The shared custody adjustment — tiered and specific

Pennsylvania has one of the most precise shared custody formulas in the country. Under Rule 1910.16-4, a specific adjustment applies once the paying parent has at least 40% of overnights per year — roughly 146 nights or more.

Unlike some states that apply a single adjustment above a threshold, Pennsylvania scales the reduction based on exactly how much time the paying parent has. The more time, the larger the reduction.

Paying parent's custody time	Approximate basic obligation reduction
Less than 40% of overnights	No adjustment — standard formula applies
40% of overnights (~146 nights/year)	Obligation reduces to approximately 58% of standard amount
45% of overnights (~164 nights/year)	Obligation reduces to approximately 53% of standard amount
50% of overnights (~182 nights/year)	Obligation reduces to approximately 48% of standard amount

It's worth noting that the 40% threshold is measured in overnights per year — 146 out of 365. Arrangements that look similar on a weekly calendar can produce different annual overnight totals depending on how holidays and summer are structured. The precise count matters.

The self-support reserve

Pennsylvania protects paying parents with lower incomes through a self-support reserve — the minimum monthly net income a paying parent keeps after child support. Under the 2026 guidelines, this reserve is $1,255 per month.

If applying the standard formula would reduce the paying parent's net income below $1,255, the obligation is reduced until the paying parent is left with exactly that amount. The reserve exists so that paying parents maintain enough income to continue working and meeting their basic needs — an obligation that leaves a parent financially unable to function generally doesn't serve anyone's long-term interests.

Add-on expenses under Rule 1910.16-6

The basic schedule amount doesn't cover everything. Pennsylvania requires parents to share additional specific expenses proportionally under Rule 1910.16-6, based on each parent's income percentage.

Required add-ons include health insurance premiums for the children, unreimbursed medical and dental expenses exceeding $250 per year per child, and work-related childcare costs necessary for a parent to maintain employment or complete their education. Private school tuition may also be ordered as an add-on if it's appropriate given the family's circumstances and financial resources.

When a court may deviate from the guidelines

Pennsylvania courts treat the guideline amount as the presumptive correct number. A deviation — up or down — requires specific findings on the record explaining why the standard result would be unjust or inappropriate.

Factors courts may consider include a child's special medical, educational, or psychological needs, the financial resources and earning capacity of each parent beyond what net income alone captures, significant differences in the households' standards of living, and any other relevant circumstances unique to the family. The party requesting the deviation carries the burden of justifying it.

If you're navigating divorce finances in Pennsylvania more broadly, our Pennsylvania divorce finances overview covers property division, alimony, and retirement accounts. We also have a dedicated guide on how alimony is calculated in Pennsylvania, including the difference between the APL formula used during divorce and the post-divorce alimony standard.

Common questions about Pennsylvania child support

When does Pennsylvania child support end? Child support in Pennsylvania typically ends when the child turns 18. If the child is still enrolled in high school at 18, support generally continues through graduation. Courts may extend support for a child with a disability. Unlike New York, Pennsylvania does not routinely order support through college.

Can Pennsylvania child support be modified? Yes. Either parent may request a modification if there's been a material and substantial change in circumstances — a significant income change for either parent, a change in the child's needs, or a change in the custody arrangement. Pennsylvania also allows either party to request a review every three years based on the passage of time alone, without needing to show a specific change.

What if a parent is self-employed? Self-employment income is included in gross income. Pennsylvania courts look at business revenue minus legitimate ordinary and necessary business expenses. Expenses that appear personal or disproportionate may be added back. Courts have authority to examine tax returns, financial statements, and business records when self-employment income is disputed.

How does Pennsylvania handle income that varies year to year? For parents with fluctuating income — commission-based workers, seasonal employees, or those with significant bonus income — Pennsylvania courts often average income over a recent period (typically two to three years) to arrive at a representative monthly figure. This prevents either parent from manipulating the timing of income to affect the support calculation.