How Washington Calculates Child Support
Washington uses the Income Shares model to determine child support obligations. This page explains the guidelines, formula, and key factors.
Model Type
Income Shares
Washington (RCW 26.19) calculates support from an economic table based on the parents' combined net monthly income -- one of the few states using net rather than gross as the base. The table is presumptive up to $50,000/month combined net income; above that, a court may exceed the table amount only with written findings.
Income Basis & Definitions
net monthly income (RCW 26.19.071)
Selects the base-support amount from the schedule/table.
Source: RCW 26.19.020 economic tableParenting Time Handling
Calculator selects custody model/worksheet (sole/shared/split/joint) and applies corresponding formula.
Source: Custody/worksheet applicability and parenting-time adjustmentResidential schedule/parenting time is handled via deviations; capture as deviation flag with details.
Source: Residential schedule deviation standardsDeductions & Adjustments
Adjustments/credits for other dependents or court-ordered support for other children (state-specific).
Source: Other children / preexisting support adjustmentIf the guideline adjusts for spousal support (paid/received), capture amount.
Source: Spousal support (alimony/maintenance) adjustmentAdd-Ons & Allocation
Work-related childcare costs added and allocated between parents.
Source: Childcare add-onChild’s health insurance premium share and uninsured/unreimbursed medical allocation.
Source: Medical support (insurance + uninsured medical)Caps, Minimums & Deviations
If guideline table caps at an income level, above-cap support is typically discretionary with findings.
Source: Maximum schedule income / above-cap handlingDeviation allowed for enumerated factors; requires findings (court-determined).
Source: Deviation factors / findings