Washington Child Support Calculator

Estimate Washington child support for 2026 using the Income Shares guideline model under RCW 26.19. Enter both parents' incomes and the parenting-time split to see what you may owe or receive.

Washington follows the Income Shares model under RCW 26.19. The court combines both parents' monthly gross incomes, looks up the basic support obligation on the state's guideline schedule for that income level and number of children, then prorates the obligation between the parents according to each parent's percentage share of the combined income.

In Washington, parenting time does not automatically change the support number the way a fixed overnight formula would. Instead, substantial residential time is treated as a deviation factor under RCW 26.19. The base obligation is first set by combining both parents' incomes, and a judge may then deviate up or down if a child spends significant time with the parent who pays support. The parent asking for the deviation must show the court why it is justified.

Health insurance for the child is treated as an add-on in Washington, separate from the basic support obligation. The premium that covers the child is shared between the parents in proportion to each parent's percentage of the combined income, the same way the basic obligation is divided. If one parent pays the full premium, the order typically credits or reimburses that parent for the other parent's proportional share.

Work-related child care, such as daycare a parent needs in order to work, is treated as an add-on cost in Washington and is not folded into the basic support number. These costs are divided between the parents in proportion to their shares of the combined income. The on-page calculator gives only an estimate, so document your actual child care expenses and confirm how they are split on the official worksheet.

Washington judges start from the standard calculation under RCW 26.19, but they may deviate from that number when the facts justify it. Recognized reasons include substantial residential time with the paying parent, income of other adults in the household, children from other relationships, and other listed factors. The parent who wants the court to depart from the guideline amount carries the burden of proving the deviation is appropriate, and the judge must put written reasons in the order.

Frequently asked questions

How is child support calculated in Washington?

Washington uses the Income Shares model under RCW 26.19, administered with help from the Washington State Division of Child Support. The court combines both parents' monthly net incomes, then looks up the basic support obligation on the state's guideline schedule for that combined income and the number of children. That obligation is split between the parents in proportion to each parent's percentage of the combined income, and add-ons like health insurance and work-related child care are layered on top. The idea is that the child receives roughly the same share of parental income that the child would have if the parents lived together. Our calculator estimates this, but the official worksheet and a licensed attorney control the final number.

Is there an official Washington child support worksheet I have to use?

Yes. Washington's child support order is built on the official state worksheet that applies the RCW 26.19 guideline schedule, and that worksheet, not an online estimate, is the controlling form the court relies on. The Washington State Division of Child Support also offers an online estimator at dshs.wa.gov for planning purposes. The worksheet walks through each parent's net income, the combined income, the basic obligation from the schedule, the proportional split, and add-ons such as insurance and child care. Our on-page tool is an estimate to help you prepare, but you must complete the official worksheet, and a licensed attorney can confirm you filled it out correctly.

What income does Washington use to figure child support?

Washington bases support on net monthly income, not gross. You start with gross income from all sources, then subtract certain mandatory deductions: federal income tax, FICA (Social Security and Medicare), mandatory retirement contributions, mandatory union dues, mandatory non-profit pension plan contributions, and existing court-ordered support you already pay. What remains is the net income the guideline schedule uses. Both parents' net incomes are combined to find the basic obligation under RCW 26.19. Because voluntary deductions do not count, your take-home pay on a paystub may differ from the net figure used in the calculation. The Division of Child Support and the official worksheet govern how each deduction is applied.

How are bonuses, overtime, and self-employment income counted in Washington?

Washington defines income broadly, so gross income from all sources is the starting point before the mandatory deductions are taken to reach net income. That generally means wages, salary, overtime, bonuses, commissions, and self-employment earnings can all be considered. For self-employed parents, the court typically looks at income after legitimate, necessary business expenses, and may scrutinize deductions that look like personal expenses. Irregular income such as seasonal overtime or yearly bonuses can be averaged so the support figure reflects a realistic monthly amount. Because these situations get fact-specific, our estimate may not capture them precisely. Use the official worksheet and consider a licensed attorney for self-employment or fluctuating income.

Can a Washington judge order a different amount than the guideline calculation?

Yes. The guideline number under RCW 26.19 is the starting point, but a Washington court can deviate from it when the facts support a departure. Listed reasons include substantial residential time with the paying parent, income of other adults in the household, nonrecurring income, children the parent supports from other relationships, and similar factors. The parent asking for the deviation must prove it is justified, and the judge has to write the reasons for any deviation into the order. This is one reason two families with similar incomes can end up with different orders. Our calculator cannot predict a deviation, so treat its output as an estimate only.

How is child support enforced in Washington if a parent does not pay?

The Washington State Division of Child Support, part of the Department of Social and Health Services, has strong enforcement tools. Most orders include immediate income withholding, so support comes straight out of the paying parent's wages. If payments fall behind, DCS can intercept state and federal tax refunds, suspend driver's, professional, and recreational licenses, file liens against property, report the debt to credit bureaus, and refer the case to court for contempt. Past-due support, known as arrears, generally keeps accruing until it is paid in full and is not erased simply because a child grows up. These enforcement steps are handled through DCS and the courts, not through this calculator.

When does child support end in Washington?

In Washington, child support generally continues until the child turns 18, or until the child graduates from high school if that happens later, but not past age 19. Support does not always stop automatically, so check the wording of your specific order. Washington also allows two important exceptions: a court can separately order post-secondary educational support to help with college or vocational school, and support can continue for an adult child who is disabled and unable to be self-supporting. Any past-due arrears remain owed even after the current obligation ends. To change or terminate an order, you file in superior court or request a review through the Division of Child Support.