How Washington calculates support
The Income Shares combines BOTH parents' incomes, looks up the guideline support amount for that combined income and the number of children, then splits the obligation between the parents in proportion to their incomes. Parenting time, health insurance, and childcare costs adjust the result.
Military BAH/BAS is included in gross income per state guidelines.
Before any court filing, confirm your number with Washington's official calculator or worksheet.
Documents you will need
- Pay Stubs, last 2-3 months
- W-2 Forms, last 2 years
- Federal Tax Return, most recent year
- Health Insurance Premium Statement
- Childcare Receipts / Provider Statement
- Existing Support Order (if applicable)
- Schedule C (Self-Employment Income)
- Business Bank Statements, 3 months
- Profit & Loss Statement
- Financial Declaration (WPF DR 01.0550) (Washington-specific)
Run your estimate and keep the record
CoreParent's calculator covers all 50 states with Washington's model, keeps your assumptions, and produces a record you can keep alongside your parenting plan and shared expenses. Support math lives best in the same system as your calendar and expense record.
This is general educational information, not legal advice, and official figures change. Last verified against published guidelines: 2026. Consult a licensed family-law attorney in Washington.