Washington Child Support Calculator

Washington uses the income shares model under RCW 26.19 to calculate child support based on both parents' combined monthly net income. The court references the Economic Table (RCW 26.19.020), which covers combined incomes from $2,200 to $50,000 per month, to determine the basic support obligation by number and age of children. Each parent pays their proportional share—for example, a parent earning 60% of combined income pays 60% of the obligation.

Washington courts count all income sources under RCW 26.19.071, including wages, commissions, bonuses, self-employment earnings, Social Security, unemployment benefits, rental income, and spousal maintenance received. Allowable deductions include federal and state taxes, FICA, mandatory pension contributions, union dues, and up to $5,000 annually in voluntary retirement contributions. Tax returns for the prior two years and current pay stubs must be provided to verify income.

Washington uses a mandatory Parenting Plan framework that assigns residential time rather than traditional custody labels. Under RCW 26.19.075, when a child spends more than 90 overnights per year with the paying parent, the court may deviate from the standard child support calculation. The deviation accounts for duplicated housing and food costs during extended residential time, potentially reducing the transfer payment.

Washington allows child support modification under RCW 26.09.170 upon showing a substantial change in circumstances that alters the support amount by at least 25% or $50 per month, whichever is greater. After 24 months, either parent can request adjustment based on income changes without proving a substantial change. Voluntary unemployment alone does not qualify as a substantial change. Modifications apply prospectively from the filing date.

Beyond the basic Economic Table obligation, Washington courts allocate additional expenses proportionally between parents under RCW 26.19.080. These include children's health insurance premiums, uninsured medical and dental costs, and work-related daycare expenses. The 2026 update removed educational expenses from the Economic Table, though courts retain discretion to address extraordinary costs through deviation findings under RCW 26.19.075.

Washington sets a minimum child support obligation of $50 per child per month under RCW 26.19.065. The Economic Table is presumptive for combined monthly net incomes up to $50,000; courts may exceed this ceiling with written findings. Child support cannot exceed 45% of the paying parent's net income, and the self-support reserve protects parents earning below 180% of the federal poverty level from obligations that would reduce their income below that threshold.

Washington child support typically continues until the child turns 18 or graduates from high school, whichever is later, per RCW 26.09.170. Support may extend beyond age 18 for children with mental or physical disabilities that prevent self-sufficiency. Either parent or the child may petition for postsecondary educational support before the child turns 18 or graduates. Early emancipation through court order, military service, or marriage can terminate support sooner.

Washington's Division of Child Support (DCS) enforces orders through wage garnishment of up to 50–65% of disposable income under RCW 26.23.060, tax refund interception, bank account liens, and property seizure. Under RCW 74.20A.320, parents owing more than six months of unpaid support face suspension of driver's, professional, and recreational licenses. Courts may hold non-paying parents in contempt under RCW 7.21.030, imposing fines or jail time, and unpaid child support debt remains enforceable for 10 years after the youngest child turns 18.