How Child Support Is Calculated in Washington

One statewide schedule

In a divorce or legal separation, the court orders either or both parents to pay child support in an amount determined under chapter 26.19 RCW (RCW 26.09.100(1)), and the same chapter applies in parentage cases (RCW 26.26B.020(6)). The schedule applies in every county, in judicial and administrative proceedings, in all proceedings in which child support is set or modified, and to temporary as well as permanent support (RCW 26.19.035(1)).

Worksheets in the form developed by the Administrative Office of the Courts must be completed under penalty of perjury and filed in every proceeding in which child support is determined, and the court may not accept incomplete worksheets or worksheets that vary from the official ones (RCW 26.19.035(3)). The current Washington State Child Support Schedule Worksheets (revised 06/2026) and the schedule, instructions, and economic table (revised 06/2026) are posted by the Washington Courts.

Step 1: each parent's monthly net income

All income and resources of each parent’s household must be disclosed, but only the income of the parents of the children in the case is used to calculate the basic support obligation (RCW 26.19.071(1)). Gross monthly income includes income from any source, including wages, salaries, commissions, overtime, bonuses, self-employment income, Social Security and disability benefits, unemployment benefits, and maintenance actually received, except for what is specifically excluded (RCW 26.19.071(3)).

• Disclosed but not counted: income of a new spouse or other adults in the household, child support received from other relationships, gifts and prizes, TANF, SSI, aged, blind, or disabled assistance, pregnant women assistance, food stamps, and some overtime or second-job income beyond 40 hours a week in the situations the statute describes (RCW 26.19.071(4)).
• Deducted to reach net income: federal and state income taxes, FICA, mandatory pension payments, mandatory union or professional dues, mandatory state deductions such as paid family and medical leave premiums, state industrial insurance premiums, court-ordered maintenance actually paid, up to $5,000 a year in voluntary retirement contributions that meet the statute’s conditions, and normal business expenses and self-employment taxes (RCW 26.19.071(5)).

Imputed income. The court must impute income to a parent who is voluntarily unemployed or underemployed. Whether a parent is voluntarily unemployed or underemployed is decided from factors such as work history, education, health, age, the local job market, and the prevailing earnings in the community. It does not impute income to a parent who is unemployable, and it does not impute income to a parent who is gainfully employed full time unless it finds the parent is purposely underemployed to reduce support (RCW 26.19.071(6)). Without records of actual earnings, the statute sets an order of priority that starts with full-time earnings at the current rate of pay (RCW 26.19.071(6)(a)).

Step 2: the economic table

The economic table in RCW 26.19.020 gives a monthly basic support obligation per child, based on the parents’ combined monthly net income and the number of children. The current table took effect January 1, 2026. It is presumptive for combined monthly net incomes up to and including $50,000; above that, the court may exceed the presumptive amount for $50,000 on written findings of fact (RCW 26.19.020, RCW 26.19.065(3)). For combined incomes below $2,200, the table says the obligation is based on the resources and living expenses of each household.

Step 3: each parent's share and added expenses

1. The basic obligation is allocated between the parents by each parent’s share of the combined monthly net income (RCW 26.19.080(1)).
2. Health care costs are not in the table and are shared in the same proportion. They include medical, dental, orthodontia, vision, mental health treatment, prescriptions, and similar costs (RCW 26.19.080(2)).
3. Day care and special child rearing expenses, such as tuition and long-distance transportation for visits, are also shared in the same proportion (RCW 26.19.080(3)). The court decides whether amounts beyond the basic obligation are necessary and reasonable (RCW 26.19.080(4)).

Limits at the low and high end

• Neither parent’s support obligation for all of that parent’s children may exceed 45 percent of net income except for good cause shown, and before applying that limit the court must consider whether it would be unjust (RCW 26.19.065(1)).
• When a parent’s monthly net income is below 180 percent of the federal poverty guideline for a one-person family, an order of at least $50 per child per month is entered unless the parent shows that would be unjust (RCW 26.19.065(2)(a)).
• The basic support obligation, not counting health care, day care, and special child rearing expenses, generally may not reduce the paying parent’s net income below a self-support reserve of 180 percent of the federal poverty level for a one-person family, subject to the presumptive minimum and the exceptions in the statute (RCW 26.19.065(2)(b) and (c)).

Deviating from the standard calculation

The court first determines the standard calculation for each parent and only then considers reasons to deviate (RCW 26.19.075(3)). Reasons include, among others, the income of a new spouse or other adults in the household when the parent asks to deviate for another reason, possession of wealth, nonrecurring income, extraordinary debt not voluntarily incurred, special needs of the children, and children from other relationships (RCW 26.19.075(1)). Agreement of the parties alone is not an adequate reason to deviate (RCW 26.19.075(5)), and the order must be supported by written findings that explain any deviation or any denial of a requested deviation (RCW 26.19.035(2)).

Changing a support order

• Substantial change. A party may petition to modify a support order at any time on a showing of substantially changed circumstances. Voluntary unemployment or underemployment of the paying parent is not, by itself, a substantial change (RCW 26.09.170(5)).
• After one year. An order may be modified without that showing if it works a severe economic hardship, to extend support for a child still in high school, or to add an automatic adjustment provision (RCW 26.09.170(8)).
• After 24 months. An order may be adjusted, without showing a substantial change, for changes in a parent’s income or in the economic table or standards. Either party starts this by filing a motion and worksheets (RCW 26.09.170(9)), using the Motion to Adjust Child Support Order, FL Modify 521 (revised 07/2023).

A modification starts with a petition and worksheets (RCW 26.09.175(1)), on the Petition to Modify Child Support Order, FL Modify 501 (revised 01/2022). If the order to be modified was entered in Washington, service is by personal service or any form of mail requiring a return receipt. The responding party’s answer and worksheets are due within 20 days after service, or 60 days if served out of state, and the case is heard on affidavits, the petition, the answer, and the worksheets unless the court allows oral testimony (RCW 26.09.175(2), (4), and (6)). A modification applies only to installments accruing after the petition or motion is filed, with a limited exception for motions to compel court-ordered adjustments (RCW 26.09.170(1)).

Unless otherwise agreed in writing or stated in the decree, support for a child ends on the child’s emancipation or the death of the parent required to pay (RCW 26.09.170(3)).

The Division of Child Support

The Department of Social and Health Services runs the Division of Child Support, which handles enforcement and payments and offers a quick estimator. The department may itself file to modify or adjust an order in the situations listed in RCW 26.09.170(10) and (11). In a case without public assistance, the route in subsection (10)(b) requires a request for review by a party or another state, a finding that the order is at least 15 percent above or below the standard calculation, and a case that meets the department’s review criteria.

Primary sources

Laws, rules and forms change. Check the current version at the source before you file.

• Chapter 26.19 RCW, child support schedule
• RCW 26.19.020, economic table
• RCW 26.19.035, application of the schedule and worksheets
• RCW 26.19.065, limits on support amounts
• RCW 26.19.071, standards for determining income
• RCW 26.19.075, deviations
• RCW 26.19.080, allocation and added expenses
• RCW 26.09.100, child support in dissolution
• RCW 26.09.170, modification and termination
• RCW 26.09.175, modification procedure
• RCW 26.26B.020, support in parentage orders
• Washington State Child Support Schedule Worksheets
• Washington State Child Support Schedule
• Petition to Modify Child Support Order, FL Modify 501
• Motion to Adjust Child Support Order, FL Modify 521
• DSHS Division of Child Support