Washington Child Support Calculator & Guide (2025)

Overview of Washington Child Support

Washington uses the Income Shares Model under RCW §26.19. This model estimates the total amount of support that would have been available to the child if the parents had remained together, then divides that responsibility between the parents proportionally based on their incomes.

Washington's approach uses net income and provides a self-support reserve to protect low-income obligors. Notably, Washington may also order post-secondary education support for children attending college or vocational school.

How Child Support Is Calculated in Washington

The Washington child support formula works as follows:

1. Determine each parent's net income: Gross income minus federal taxes, Social Security, Medicare, and other allowable deductions
2. Combine both parents' net incomes to find the total household income
3. Look up the base support obligation from the Washington State Child Support Schedule based on combined income and number of children
4. Allocate each parent's share proportionally based on their percentage of the combined income
5. Add health insurance premiums and childcare costs to the base obligation
6. Apply any adjustments such as standard calculation deviations or extraordinary expenses

Key Factors in Washington Calculations

Net Income

Washington uses net income for child support calculations. This means gross income from all sources minus federal income taxes, Social Security taxes, Medicare taxes, and other mandatory deductions.

Self-Support Reserve

Washington provides a self-support reserve of $1,190 per month (2024). If the obligor parent's income falls at or near this level, their support obligation may be reduced to ensure they can meet their own basic living needs.

Post-Secondary Education Support

Washington is one of the few states that may order parents to contribute to a child's post-secondary education expenses, including college tuition, room and board, and vocational training costs. This is separate from regular child support and is subject to specific statutory criteria.

Minimum and Maximum Amounts

Minimum: While Washington does not have a fixed statutory minimum, the self-support reserve protects low-income parents from excessive obligations.

High-income cases: For combined incomes above the guideline table, the court has discretion to determine an appropriate support amount based on the child's needs and the parents' ability to pay.

Modification and Enforcement

Modification

Washington allows modification when:

• There has been a substantial change of circumstances
• A significant change in either parent's income occurs
• Custody arrangements change
• The child's needs change

Enforcement

The Washington State Department of Social and Health Services - Division of Child Support enforces child support through:

• Income withholding from paychecks
• Tax refund interception
• Driver's license suspension
• Professional license suspension
• Credit bureau reporting
• Contempt of court proceedings
• Liens on property and financial accounts

Get your Washington estimate: Use our free Washington child support calculator to see what you might owe or receive under Washington guidelines.