Child Support in Washington: Guidelines and Calculations

A couple in Snohomish County with two children and a combined net income of $18,000 per month found themselves in unfamiliar territory when calculating child support. Under the old Washington guidelines, the economic table capped out at $12,000 in combined monthly net income, and the court had broad discretion to set support for the portion above that cap. When the expanded economic table took effect on January 1, 2026, coverage jumped to $50,000 per month — and their entire income fell within the structured formula. Their support obligation went from a judge’s best estimate to a specific number on a table. The change affected thousands of Washington families, particularly in the Seattle metro area and Eastside communities where dual-income households routinely exceed the old cap.

Understanding how Washington calculates child support helps you plan financially and negotiate effectively. This guide covers the current formula under RCW 26.19, the significant 2026 updates, how residential time affects the calculation, and the rules for modification and enforcement. For a national overview, see our guide on child custody laws explained, and try our child support calculator for a quick estimate.

How Washington Calculates Child Support

Washington uses the Income Shares Model for child support, the same framework used by approximately 40 states. The principle: children should receive the same proportion of parental income they would have received if the family remained intact.

The calculation uses both parents’ net monthly incomes (not gross), determines the total child support obligation from a statutory economic table, and divides that obligation proportionally based on each parent’s share of the combined income.

Step-by-Step Calculation

Step 1: Determine each parent’s gross monthly income. Washington defines gross income broadly, including:

• Wages, salaries, commissions, bonuses, overtime
• Self-employment income (gross receipts minus ordinary and necessary business expenses)
• Dividends, interest, rental income, trust income
• Social Security, veterans’ benefits, disability benefits
• Unemployment compensation, workers’ compensation
• Spousal maintenance received
• Pensions and retirement income
• Imputed income (if voluntarily unemployed or underemployed)

Step 2: Calculate net income. Washington uses net income, not gross, for child support calculations. Deductions include:

• Federal and state income taxes
• FICA (Social Security and Medicare taxes)
• Mandatory union or professional dues
• State-mandated insurance premiums (including Paid Family and Medical Leave and WA Cares Fund premiums, as of 2026)
• Mandatory pension or retirement contributions
• Normal business expenses for self-employed parents

Step 3: Combine both parents’ net incomes. The combined monthly net income determines where the case falls on the economic table. As of January 2026, the table covers combined net incomes up to $50,000 per month (up from $12,000 previously).

Step 4: Find the basic support obligation. Using the economic table in the Washington State Child Support Schedule, look up the combined net income, the number of children, and the children’s ages. The table provides the total monthly basic support obligation.

Step 5: Divide proportionally. Each parent’s share equals their percentage of the combined net income. If Parent A earns 60% and Parent B earns 40%, those percentages apply to the total obligation.

Step 6: Add extraordinary expenses. Health insurance premiums for the children, work-related childcare costs, and long-distance transportation costs (for residential schedule exchanges) are added to the basic obligation and divided proportionally.

Step 7: Apply the transfer payment. The parent with less residential time pays their share of the total obligation (minus any direct costs they already cover, such as the child’s health insurance) to the other parent as a monthly transfer payment.

The January 2026 Updates

House Bill 1014, effective January 1, 2026, made several significant changes to Washington’s child support framework:

Expanded economic table. The presumptive guidelines now cover combined net monthly incomes up to $50,000 (previously $12,000). This is the largest expansion in the table’s history and means more families fall within the guidelines rather than relying on judicial discretion.

Higher self-support reserve. The self-support reserve increased from 125% to 180% of the federal poverty level for a one-person household. A parent’s basic support obligation cannot reduce their income below this threshold. This protects low-income parents from support orders that would push them into poverty.

Higher income floor. The bottom of the economic table increased from $1,000 to $2,200 in combined monthly income. The minimum monthly support obligation remains $50 per child for parents below this floor.

New deductions. Parents may now deduct mandatory state insurance premiums — including Paid Family and Medical Leave (PFML) and WA Cares Fund premiums — from gross income when calculating net income.

No change in the middle. Support obligations for combined incomes between $2,200 and $12,000 per month remain unchanged. The existing economic table amounts in this range were not adjusted.

These changes affect both new cases and existing orders that come up for modification. The new guidelines themselves can serve as a basis for requesting modification of a pre-2026 order.

What Counts as Income (and What Doesn’t)

Washington’s definition of gross income is broad but has limits.

Included:

• All employment income (wages, salary, bonuses, commissions, tips, overtime)
• Self-employment earnings (gross receipts minus ordinary and necessary business expenses)
• Investment income (dividends, interest, capital gains, rental income)
• Government benefits (Social Security, VA benefits, disability, unemployment, workers’ compensation)
• Retirement income (pensions, annuities, IRA distributions)
• Trust and estate income
• Spousal maintenance received
• Imputed income for voluntarily unemployed or underemployed parents

Not included:

• Income of a new spouse or domestic partner
• Child support received for other children
• Benefits from means-tested public assistance programs (TANF, SSI, food stamps)
• Overtime income if it is not consistent and reliable

Imputed Income

If a parent is voluntarily unemployed or underemployed, the court may impute income — assigning an earning capacity based on education, work history, skills, job market conditions, and prior earnings. However, voluntary unemployment or underemployment by itself is not a substantial change of circumstances for purposes of modifying an existing order under RCW 26.09.170.

The court considers whether the parent’s reduced income was voluntary, whether they made reasonable efforts to find employment, and whether the employment choice serves the child’s best interests (for example, a parent who reduces hours to care for a young child may not have income imputed).

How Residential Time Affects Support

Washington’s child support calculation accounts for the residential schedule in the parenting plan.

Standard Calculation

When one parent has the child for a majority of residential time, the other parent pays their proportional share of the basic support obligation as a transfer payment.

Residential Time Credit

When a parent has the child for a significant amount of residential time, the court may deviate from the standard support calculation. Washington does not use a specific threshold (like 90 or 110 overnights) for automatic adjustments. Instead, the court considers whether the residential schedule significantly affects the relative cost of raising the child for each parent.

Equal residential time (50/50) does not automatically eliminate child support. Even with equal time, if one parent earns significantly more than the other, a transfer payment may be ordered to ensure the child has a comparable standard of living in both homes.

Health Insurance and Medical Costs

Health insurance for the children is a mandatory component of Washington child support orders.

• The cost of the child’s share of health insurance premiums is added to the basic support obligation and divided proportionally between the parents
• Uninsured medical, dental, and mental health expenses are typically split based on income shares
• The court designates which parent provides coverage based on availability and cost
• If neither parent has employer-sponsored coverage, the court may order coverage through the Health Insurance Marketplace or Apple Health (Washington’s Medicaid program)

Modifying Child Support

Washington child support orders can be modified when circumstances change.

Substantial Change in Circumstances

To modify support outside of a routine review, you must show a substantial change in circumstances under RCW 26.09.170. Qualifying changes include:

• Job loss or significant income change
• Change in the residential schedule
• Increased childcare or medical expenses
• A child’s emancipation (when multiple children are covered)
• The January 2026 guideline changes (for pre-existing orders)

Voluntary unemployment or underemployment, by itself, is not sufficient to constitute a substantial change.

24-Month Review

After 24 months from entry or the last modification, either parent can petition for a review and adjustment without showing a substantial change. The court recalculates using current incomes and the current economic table. If the adjustment exceeds 30%, the court may implement it in two equal steps over six months.

Economic Hardship

If the existing order causes a severe economic hardship to either parent or the child, modification may be available after 12 months without showing a substantial change in circumstances.

Effective Date

Modifications are effective from the date the motion is filed with the court, not retroactively. File promptly when your circumstances change.

When Child Support Ends

In Washington, child support typically ends when the child turns 18. However, if the child is still enrolled in high school at age 18, support continues until graduation or age 19, whichever comes first.

Post-Secondary Support

Washington is one of a limited number of states that allows courts to order parents to contribute to a child’s post-secondary education expenses. Under RCW 26.19.090:

• Either parent may petition the court for an order of post-secondary support
• The court considers the child’s needs, each parent’s financial resources, the child’s academic performance, and the amount the child can contribute through employment and financial aid
• Support may cover tuition, room and board, books, and transportation
• Post-secondary support is not guaranteed — the court has discretion
• The Division of Child Support (DCS) cannot order post-secondary support; it must be ordered by a superior court judge

This provision makes Washington distinctive. Most states, including neighboring Oregon and Idaho, do not allow courts to order college support.

Enforcement

Washington has robust enforcement tools for child support, administered through the Division of Child Support (DCS).

• Income withholding — the default method; support is deducted directly from wages
• Bank account garnishment — DCS or the court can levy bank accounts, including joint accounts, up to the amount of arrears
• Tax refund interception — federal and state refunds redirected to cover arrears
• License suspension — driver’s, professional, and recreational licenses suspended until payment arrangements are established
• Passport denial — for arrears exceeding $2,500 under federal law
• Property liens — placed on real estate, vehicles, and other assets
• Contempt of court — willful failure to pay can result in fines and jail time
• Credit reporting — delinquent support reported to credit bureaus

Washington allows enforcement for up to 30 years after the youngest child ages out of the order. Child support arrears are nondischargeable in bankruptcy.

Incarceration Provisions

Support may be abated to $10 per month per order during incarceration. Upon release, the parent may seek modification without showing a substantial change in circumstances. Starting April 1, 2027, support may also be abated to $50 per month per child during court-ordered behavioral health treatment.

Frequently Asked Questions

How much is child support in Washington for one child?

It depends on both parents’ combined net incomes and the residential schedule. As a rough example, for combined net monthly income of $8,000 with one child age 6-11 under a primary residential arrangement, the basic monthly obligation is approximately $900 to $1,100 before adjustments for health insurance and childcare. Use the Washington child support calculator or our child support calculator for an estimate based on your numbers.

Does child support end at 18 in Washington?

Usually, yes. Child support ends when the child turns 18. If the child is still a full-time high school student at 18, support continues until graduation or age 19, whichever comes first. Additionally, Washington courts may order post-secondary educational support, which can extend financial obligations beyond age 18 for college expenses.

Can Washington courts order parents to pay for college?

Yes. Washington is one of the few states where courts can order post-secondary educational support. The court considers the child’s needs, academic performance, each parent’s financial resources, and the child’s ability to contribute. Post-secondary support must be ordered by a superior court judge — the Division of Child Support cannot order it.

How does equal residential time affect child support in Washington?

Equal residential time (50/50) does not automatically eliminate child support. If one parent earns significantly more than the other, the court may still order a transfer payment so the child has a comparable standard of living in both homes. The court considers the residential schedule as one factor but does not apply an automatic credit for equal time.

Can child support be modified if I lose my job?

Yes. Involuntary job loss constitutes a substantial change in circumstances that justifies a modification. File a motion promptly — modifications are effective from the filing date, not retroactively. If you voluntarily quit or reduce your hours, the court may impute income based on your earning capacity rather than your actual income.

How This Guide Was Researched

This guide was created by reviewing publicly available legal information from official state statutes, judiciary websites, court resources, and family law publications. The goal is to explain family law topics in plain English so readers can better understand the process before speaking with an attorney.

Sources and Legal References

This guide is based on publicly available legal information and official sources, including:

• RCW 26.19 — Child Support Schedule
• RCW 26.19.065 — Standards for Child Support Amounts (2026)
• RCW 26.19.090 — Post-Secondary Educational Support
• RCW 26.09.170 — Modification of Child Support
• Washington’s New Child Support Rules 2026 — Lasher Holzapfel Sperry & Ebberson
• Washington DCS — Child Support Calculator

Official Washington Resources

• Division of Child Support (DCS)
• Washington Courts — Court Forms
• Washington Law Help — Child Support
• Washington Legislature — RCW Title 26

For more about how we research our guides, see our editorial policy and sources methodology.

Related Guides

Learn more about related family law topics:

• Divorce in Washington
• Child Custody in Washington
• Child Support Calculator
• Child Custody Laws Explained
• How Much Does Divorce Cost?
• The Complete Guide to Divorce
• Get a Free Consultation

Last updated: March 2026. This guide summarizes general legal information based on publicly available sources and is provided for educational purposes only. It does not constitute legal advice. For advice specific to your situation, consult a licensed attorney in your state.