Combined net income is the total sum of both Parent 1 and Parent 2's monthly income after all mandatory state deductions (like taxes, union dues, and L&I) are removed.
RCW 26.19.071 requires both parents to disclose all income sources. Combined monthly net income is calculated by adding both parents net monthly incomes after all mandatory deductions are subtracted from gross income. It is entered on Line 4 of the WSCSS worksheet.
Step 1 — Calculate each parent's gross income: Include all sources: wages, salaries, business income, rental income, investment income, pension, Social Security, unemployment benefits, and maintenance received. Understanding this term is important when completing your child support calculation. Use our worksheet calculator to see how this applies to your case.
Step 2 — Subtract mandatory deductions per parent: Federal and state income taxes actually owed. FICA: Social Security 6.2% plus Medicare 1.45%. Mandatory state deductions including paid family and medical leave and long-term care premiums. Mandatory union or professional dues. Required pension plan payments. Court-ordered maintenance actually paid.
Step 3 — Add both parents net incomes: P1 net income + P2 net income = Combined net income
Step 4 — Round to nearest $100 for table lookup: Round down if last two digits are 49 or less. Round up if last two digits are 50 or more. Example: $5,480 rounds up to $5,500. Example: $5,449 rounds down to $5,400.
Combined net income determines which row of the 2026 economic table applies to your case. Higher combined income generally means a higher basic obligation per child. The table covers combined incomes from $2,200 to $50,000 per month. Above $50,000 the court may exceed the maximum presumptive amount with written findings.
No. Only the income of the two parents of the children in this case is included. New spouse or domestic partner income is disclosed separately but not included in the calculation.
Use our 2026 Washington State estimator to see how these legal terms impact your support amount. All calculators are RCW 26.19 compliant.