Like all states in the U.S., Washington State has guidelines that are meant to give judges and parents predictable, consistent rules for determining the appropriate amount of child support that parents should pay when they're divorced or not living together. The guidelines apply when parents first get divorced or split up, as well as when they later want to change the amount of support they're paying or receiving.
The process of calculating child support can be complicated. The state does provide some tools you can use (more on that below). But before you start, it will help to understand how the guidelines work and what you'll need to begin.
Both parents are legally required to support their children financially. When parents are divorced, separated, or were never married, the parent who doesn't have physical custody of the children most of the time (the "noncustodial parent") typically pays child support to the custodial parent.
This doesn't mean custodial parents are off the hook for their support obligation. Washington State's guidelines calculate both parents' support obligation, based on each one's proportionate share of their combined incomes. While noncustodial parents make child support "transfer" payments to cover their share, the state presumes that custodial parents meet their support obligation by paying directly for the child's daily expenses, like housing, food, and clothing.
When the parents have split custody—meaning that each parent has physical custody of at least one of their children—the question of who pays child support will depend largely on their respective incomes and how many children live with each parent.
The first step in calculating child support is to gather information about each parent's monthly gross income and the allowed deductions from that amount.
Gross income includes:
Sources of income that are not included in gross income include public assistance that's based on need (such as SSI or food stamps) and income from a new spouse, partner, or other adults in your household.
Net income is gross income minus the following deductions:
(Wash. Rev. Code § 26.19.071 (2024).)
If parents are voluntarily unemployed or underemployed, judges in Washington must use imputed income to calculate child support. Judges will consider a range of circumstances when deciding whether a parent is unemployed or underemployed, including:
The guidelines spell out how judges will decide on an amount of imputed income when there isn't a record of a parent's actual earnings. (Wash. Rev. Code § 26.19.071(6) (2024).)
After the basic child support obligation is calculated, based on parental income and the number of children being supported, Washington's guidelines allow various adjustments.
Washington's guidelines includes adjustments for the following child-related expenses:
The parent who actually pays these expenses will then get a credit in the child support calculation. (Wash. Rev. Code § 26.19.080 (2024).)
The calculation of child support in Washington also includes adjustments and limits for low-income and high-income parents:
(Wash. Rev. Code § 26.19.065 (2024).)
Unlike in many other states, Washington's guidelines don't include a built-in adjustment for shared custody in the standard child support calculation. Instead, noncustodial parents with significant parenting time—or parents with equal shared custody—will need to request a deviation from the standard child support calculation (more on that below).
Washington judges will presume that the amount of child support resulting from the standard calculation is appropriate, unless either parent can demonstrate that it would be unfair not to order a different amount. (Wash. Rev. Code § 26.19.011(9) (2024); In re Marriage of Selley, 359 P.3d 891 (Wash. Ct. App. 2015).)
The guidelines list some of the reasons a judge may allow a deviation from the standard calculation, including when:
Judges won't necessarily allow a deviation even in any of these situations. Rather, they'll consider whether it would be unfair not to order a support amount that's different than the standard calculation. For instance, in a case where the parents had 50/50 shared custody but the father earned 10 times more than the mother, an appeals court upheld the judge's decision to deny the father's request for a deviation. (Wash. Rev. Code § 26.19.075 (2024); Marriage of Condie, 475 P.3d 993 (Wash. Ct. App. 2020).)
If you and your child's other parent have agreed on an amount of child support that deviates from the standard calculation, be prepared to explain the reasons it would be best for your children. A judge must approve your agreement before making it part of an official support order. Judges will usually approve agreements for child support above the guideline amount, but they'll take a much closer (and more skeptical) look if you've agreed to a lower amount.
Normally, child support ends in Washington when a child when a child turns 18 or is otherwise emancipated. Support may continue until the child's 19th birthday if the child is still attending high school or an equivalent program, but a parent will need to request a modification to extend the support order in that situation. (Wash. Admin. Code § 388-14A-3810; Wash. Rev. Code § 26-09-170(8)(b) (2024).)
Beyond those limits, judges in Washington may order parents to pay support for their children's expenses for postsecondary education (at an accredited college or vocational school), as long as the children are actually dependent on their parents and relying on them to pay for their reasonable necessities. When deciding whether to award postsecondary support, judges will consider all of the circumstances, including:
Any postsecondary child support will end when the child turns 23, except when there are exceptional circumstances (such as when the child has disabilities).
(Wash. Rev. Code § 26.19.090 (2024).)
When you have children and are filing for divorce or legal separation in Washington, child support will be addressed as part of that legal process. You'll need to submit your completed child support worksheet along with your other divorce paperwork and documentation of your income (such as tax returns and pay stubs).
If you aren't married to your child's other parent, you may get help with requesting support by enrolling for child support services with the Division of Child Support (DCS) in the Washington State Department of Social and Health Services.
Typically, parents pay child support by having the payments withheld from their wages and then forwarded to the other parent. If you're having trouble collecting support, you can get help from the Washington DCS or the court. Depending on how much the noncustodial parent owes, the agency and courts have a number of tools to enforce child support in Washington.
Either parent may request a change in an existing child support order. The requirements for modifications are different depending on how long it's been since the existing order was issued or last adjusted. (Learn more about modifying child support in Washington State and how a parent's remarriage might affect child support.)
You can use Washington's Quick Child Support Estimator to get a very rough idea of the amount of child support you might pay or receive, based only on the parents' take-home pay and the number of children. But this tool doesn't include any of the adjustments and credits allowed under the state's guidelines (discussed above).
For a more accurate calculation, you should use the Washington State Child Support Schedule worksheet. Once you fill in your information, the automated worksheet will do the calculations for you. You can then print the worksheet and submit it to the court as part of your divorce or other child support proceeding.
If you have questions about filling in the worksheet, the Washington State Child Support Schedule includes instructions. You can find the schedule, as well as the attachment for the split custody adjustment on the Washington Court Forms page for child support.
It's important to remember that the amount of child support shown on the completed worksheet might not apply in your case if a judge decides that ordering that standard calculation would be unfair under the circumstances. If you're requesting a deviation from the guidelines, it would be wise to speak with a family lawyer who can explain how the law applies to your situation and can help you make your case before the judge.