How Pennsylvania Calculates Child Support

Pennsylvania uses the Income Shares model to determine child support obligations. This page explains the guidelines, formula, and key factors.

Model Type

Income Shares (Pa.R.Civ.P. 1910.16-4, Formula 1)

Pennsylvania looks up a basic support obligation from the § 1910.16-3 statutory schedule by combined net income, prorated by each parent's income share. The higher-earning parent (the obligor) gets a reduction only once their own overnights reach 40% -- below that, the schedule already assumes 30% and no adjustment applies.

Sources & Verification

Core formula verified; some gaps disclosed below

Guideline effective 2026-01-01 · last checked against the primary source 2026-08-14

Primary sources

Pa.R.Civ.P. 1910.16-2 — Support Guidelines. Calculation of Net Income Pa.R.Civ.P. 1910.16-3 — Support Guidelines. Basic Child Support Schedule Pa.R.Civ.P. 1910.16-3.1 — Support Guidelines. High-Income Cases Pa.R.Civ.P. 1910.16-4 — Support Guidelines. Calculation of Support Obligation, Formula Pa.R.Civ.P. 1910.16-6 — Support Guidelines. Allocation of Additional Expenses

What this calculator doesn't yet handle

Implements Formula 1 (orders on/after 2019-01-01) only; Formula 2 (pre-2019 orders) is not implemented.
The 575-row basic support schedule was transcribed programmatically from the PA Code HTML and validated against 11 independent anchor cells and full monotonicity, but the source page itself contains a data-quality defect for combined incomes $26,000-$29,950 across the 2-6 child columns (values nearly frozen, inconsistent with the schedule's own high-income extension). That band was patched via linear interpolation between the last clean row ($25,950) and the verified $30,000 row — see the header comment in shared/pa-schedule.ts.
Pennsylvania's rule gives no interpolation instruction for combined income between $50 schedule rows (unlike Virginia, which explicitly directs interpolation). This calculator rounds to the nearest $50 row instead; the measured divergence from interpolation is under 1% above $4,000 combined income. See docs/pa-calculator-spec.md §26.
Split custody (one or more children living primarily with each parent) is not implemented — the calculator collects a single overnight split for all children, consistent with the guideline's own preference for averaging over per-child calculation, but cannot compute the offset method Pa.R.Civ.P. 1910.16-4 describes for true split-custody cases.
The 'equal custody' threshold that triggers the income-equalization ceiling is not defined by rule text as an exact band; this calculator treats an overnight split within one night of 50/50 as equal, which is a documented judgment call.
The obligor's income share is rounded to the nearest whole percentage point before being applied, matching the rule's own worked examples (68% and 53%, not 68.49% or 52.63%) exactly, but this is inferred from example precision rather than stated as an explicit rounding rule in the text.
Income imputation for a party who fails to obtain appropriate employment (mandatory under Pa.R.Civ.P. 1910.16-2, based on 13 fact-intensive factors) is not calculated, only disclosed.
Existing child support orders for other children, spousal support/APL interaction, private school tuition, camp, and extracurricular allocation, and the discretionary Step Three high-income adjustment are not calculated, only disclosed.
Judicial deviations under Pa.R.Civ.P. 1910.16-5 are not predicted, consistent with every other calculator on this site.
Pay frequency (weekly/biweekly conversion) is not collected as a separate input — unlike New Hampshire, no PA-specific conversion practice was confirmed during research, so only monthly income is accepted rather than guessing an unconfirmed multiplier.