Pennsylvania Child Support Formula
Complete guide to understanding how Pennsylvania calculates child support under the income shares model, including high-income formulas, shared custody adjustments, and additional expense allocation.
Quick Facts
Overview of the Pennsylvania Formula
Pennsylvania uses the income shares model for child support calculations, governed by Pennsylvania Rules of Civil Procedure (Pa.R.C.P.) Rules 1910.16-1 through 1910.16-7. This model is based on economic research showing that children should receive the same proportion of parental income they would have received if their parents lived together in an intact household.
The formula uses a statewide schedule of Basic Child Support Obligations for combined monthly net incomes up to $30,000. For higher incomes, specific formulas apply. The calculation considers both parents' net incomes, the number of children, parenting time arrangements, and mandatory additional expenses like health insurance and childcare.
Step-by-Step Calculation Process
Start with gross income from all sources (wages, self-employment, investments, retirement, etc.). Subtract only allowable deductions: federal/state/local taxes, FICA, mandatory union dues, mandatory retirement contributions, and alimony paid to other party.
Combined Monthly Net Income (CMI) = Parent A net income + Parent B net income. This determines which calculation path to use: standard schedule (≤$30,000), high-income formula (>$30,000), or low-income special calculation.
For CMI ≤$30,000, use Pennsylvania Schedule. For CMI >$30,000, apply high-income formula with marginal percentages (4.0%-6.3% above $30,000 threshold). Low-income cases use special dual-calculation method.
Calculate each parent's percentage of combined income. Multiply Basic Obligation by obligor's percentage share. The non-custodial parent (obligor) pays their share to the custodial parent.
If obligor has ≥40% overnights, apply shared custody reduction. Add prorated shares of health insurance premiums, childcare costs, and unreimbursed medical expenses (>$250/child/year).
Three Calculation Paths Based on Income
Pennsylvania law provides three distinct calculation methodologies depending on the parents' combined income:
Use the Pennsylvania Schedule of Basic Child Support Obligations to look up the total obligation based on combined monthly net income and number of children. Then apportion this amount between parents based on their respective income percentages.
Example:
Combined income $5,000, 2 children → Schedule shows $1,355 total obligation. If Parent A earns 60% of combined income, they owe $813/month.
When obligor's monthly net income is at or below the Self-Support Reserve ($1,063), perform TWO calculations: (A) using only obligor's income, and (B) using combined income method. The obligor pays the LESSER of the two amounts.
Purpose:
Ensures the support order doesn't reduce the obligor's income below the minimum needed for their own basic subsistence, while still providing support for the child.
Apply statutory formulas with marginal percentages above the $30,000 threshold:
High-Income Formulas:
- 1 child: $3,608 + 4.0% of (CMI - $30,000)
- 2 children: $4,250 + 4.0% of (CMI - $30,000)
- 3 children: $4,951 + 4.7% of (CMI - $30,000)
- 4 children: $5,530 + 5.3% of (CMI - $30,000)
- 5 children: $6,083 + 5.8% of (CMI - $30,000)
- 6 children: $6,613 + 6.3% of (CMI - $30,000)
Shared Custody Adjustment
Shared Custody Formula
- Calculate obligor's time percentage: (Obligor's annual overnights ÷ 365) × 100
- Calculate custody credit percentage: Time percentage - 30%
- Calculate adjusted income share: Obligor's income % - Custody credit %
- Apply to obligation: Basic obligation × Adjusted income share
Example:
Obligor has 182 overnights (49.86% time). Custody credit = 49.86% - 30% = 19.86%. If obligor's income share is 60%, adjusted share = 60% - 19.86% = 40.14%. Their adjusted support obligation is Basic obligation × 40.14%.
Additional Expenses Allocated Separately
Certain expenses are not included in the basic support schedule and must be allocated between parents in proportion to their net incomes:
The portion of health insurance premiums covering the children is allocated proportionally.
Reasonable Cost Limit: Cannot exceed 5% of paying parent's monthly net income.
Reasonable work-related childcare expenses are allocated proportionally.
Tax Credit Adjustment: Total childcare cost is reduced by the federal Child Care Tax Credit value before allocation.
Medical, dental, and vision expenses not covered by insurance.
$250 Threshold: Only expenses exceeding $250 per child per year are allocated.
Frequently Asked Questions
Related Resources
References & Accuracy
Editorial Review
Primary Legal Sources
- statutePa.R.C.P. 1910.16-1 – Support obligation and guidelines
- statutePa.R.C.P. 1910.16-2 – Monthly net income calculation
- statutePa.R.C.P. 1910.16-3 – Basic child support schedule
- statutePa.R.C.P. 1910.16-3.1 – High-income formulas
Internal Research: This page incorporates proprietary analysis of Pennsylvania child support law, including technical specifications of the income shares model and shared custody calculations. For additional context, see our Pennsylvania Calculator and Family Law Guide.