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📊Calculating Child Support in Washington State

by | Jul 10, 2025 | Family Practice

Guidance for Family Law Attorneys at Althauser Rayan Abbarno

Calculating child support in Washington involves a structured Income Shares Model, mandated by RCW 26.19. Here’s a comprehensive overview for family law practitioners:

1. Determine Each Parent’s Gross Income

All income sources—wages, commissions, bonuses, self‑employment, unemployment, workers’ comp, Social Security, interest, dividends, dividends, rental income, spousal maintenance, etc.—must be included.

2. Identify Allowable Deductions

Deduct federal/state taxes, FICA (Social Security and Medicare), mandatory pension dues, union dues, L&I premiums, business expenses, court-ordered spousal support, and up to $5,000 annually in voluntary retirement contributions.

3. Compute Net Monthly Income & Combined Income

Subtract deductions to find each parent’s monthly net income. Sum both parents’ net incomes to determine combined monthly net income.

4. Refer to the Economic Table

Use the combined income and the number of children to locate the basic support obligation on the economic table in RCW 26.19.020.

  • Minimum: $50 per child/month
  • Applies to income up to $12,000/month; statutory caps limit support to 45% of net income beyond that, unless deviation is warranted.

5. Allocate the Obligation Proportionally

Each parent’s share equals their fraction of combined net income multiplied by the basic obligation (per RCW 26.19.080).

6. Add Necessary Expenses

Allocate additional costs—health insurance premiums, uninsured medical costs, childcare, educational or extracurricular expenses—proportionally.

7. Apply Deviations (if justified)

Under RCW 26.19.075, authorized deviations include:

  • Nonrecurring income (bonuses, overtime)
  • Extraordinary debt or expenses
  • Special needs of children
  • Parenting time adjustments (residential schedule)
  • Prior obligations to children from other relationships.

Deviations must be clearly supported with written findings and compliant with RCW 26.19.071 standards.

8. Document and File Worksheets

Per RCW 26.19.004 and definitions in RCW 26.19.011, every support order must include a standard calculation worksheet and written findings. Worksheets must be completed under penalty of perjury and attached to the decree.

✅ Tips from the Attorneys at Althauser Rayan Abbarno

  • Double-check income verification: tax returns and current pay stubs are mandatory per RCW 26.19.071(2).
  • Watch for imputed income: voluntarily underemployed parents may have income imputed.
  • Mind expense thresholds: health care and childcare costs often tip the balance on deviations.
  • Ensure robust findings: any deviation or departure from standard support must be backed by explicit findings per RCW 26.19.004(2).

🧑‍⚖️ Let Althauser Rayan Abbarno Help

Child support calculations can be overwhelming—especially when combined with custody disputes or financial stress. Our family law attorneys offer experienced, compassionate, and knowledgeable legal counsel.

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📞 Call for a Consultation: (360) 736-1301
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