Child Support Calculator Washington - Guidelines & Rates

Overview

Washington child support is calculated using the Washington state child support schedule in RCW 26.19.020. That schedule sets the “basic child support obligation” based on the parents’ combined monthly net income and the number and ages of the children.

DocketMath’s Alimony Child Support Calculator (Washington) uses those Washington rules as the core framework. It helps you generate an estimated guideline obligation, and lets you see how changes to key inputs—like income, parenting time inputs (if applicable), and the children’s ages—can change the result. This is a calculator page, not legal advice. Treat outputs as planning estimates, not a court-ordered amount.

What the Washington child support schedule requires

Under RCW 26.19.020, the legislature adopts an economic table. In practice, that means:

• You start with combined monthly net income of both parents.
• You select the table row that matches that income level.
• You choose the table column for the number and ages of the children.
• You then apply the worksheet/standards process described in RCW 26.19.071 and any permitted adjustments or deviations under RCW 26.19.075.

DocketMath is designed to reflect this overall structure so you can check the math quickly and try different scenarios.

Where maintenance (alimony) fits in

Washington also has maintenance (alimony) rules in RCW 26.09.090. In real cases, “alimony” and “child support” can interact indirectly because the child support worksheet uses net income concepts. If maintenance affects a party’s net income (or the way income is characterized), it can change the inputs that flow into the child support guideline calculation.

DocketMath’s Washington calculator is intended to help you model those inputs consistently under the Washington guideline framework. It cannot confirm how a court will treat your specific facts, but it can help you estimate how changes to inputs might affect the guideline result.

Limitation period

Washington child support does not operate under a single, simple “limitation period” concept that bars guideline calculations going forward in the same way people often think about limitations in other legal contexts. Instead, the practical distinction is:

• Current / prospective child support: you calculate based on the relevant facts (like current income and parenting-time facts) using the guideline framework in RCW 26.19.020 and RCW 26.19.071.
• Past-due (arrears) amounts: enforcement and collection of past-due support are governed by additional statutes not included in the required list you provided.

Because this page is focused on the Washington guideline framework you specified—RCW 26.19.020, RCW 26.19.071, RCW 26.19.075, and RCW 26.09.090—it keeps the focus on how the guidelines are calculated, not on an arrears enforcement timeline.

Key exceptions

Washington guidelines are applied first, and then adjustments may be considered only under defined conditions. The statutes most relevant to exceptions in this context are:

• Deviations: RCW 26.19.075 permits a court, in appropriate circumstances, to deviate from the guideline amount.
• Worksheet/standards method: RCW 26.19.071 governs how the worksheet is completed and how the standards approach is applied.

Common adjustment themes (practical, not a guarantee)

While the exact deviation analysis depends on case facts and the court’s findings, the calculator can still help you understand where non-standard outcomes might come from:

• Parenting time / schedule differences can change components of the guideline worksheet calculations.
• Child age mix matters because the schedule is based on ages, not just the number of children.
• Income assumptions matter because the schedule starts with combined monthly net income, and different income inputs can shift the guideline baseline.

To summarize the statutory logic for your expectations:

• The baseline comes from RCW 26.19.020 (economic table).
• The worksheet/standards process comes from RCW 26.19.071.
• Deviations are governed by RCW 26.19.075.

What this means for a calculator result

A calculator estimate generally tracks the schedule/worksheet baseline. But deviations (the “exception path”) may require additional facts and court discretion. If your goal is a guideline estimate, focus on the schedule-driven inputs. If your goal is anticipating a potentially non-guideline outcome, you may need more than a purely numeric input run.

Statute citation

Washington’s guideline framework for child support is codified in these statutes:

• RCW 26.19.020 — Washington state child support schedule
  The basic child support obligation is determined from the economic table based on parents’ combined monthly net income and the number and ages of the children.

  • Source: https://app.leg.wa.gov/RCW/default.aspx?cite=26.19.020

• RCW 26.19.071 — Worksheet/standards
  Governs how the worksheet is completed and how the standards approach is applied.

• RCW 26.19.075 — Deviations
  Addresses when and how a guideline amount may be adjusted away from the scheduled guideline result.

• RCW 26.09.090 — Maintenance
  Governs maintenance (alimony). In practice, maintenance can affect net income inputs relevant to guideline modeling.

Use the calculator

Get a Washington guideline estimate in minutes using DocketMath at: /tools/alimony-child-support

If you want results that align with the Washington schedule framework in RCW 26.19.020, make sure your inputs reflect the guideline concepts:

Inputs that most affect the outcome

Use this checklist while filling in DocketMath:

• Combined monthly net income (both parents’ net income totals)
• Number of children
• Children’s ages (these determine the schedule column)
• Parenting-time inputs (if your calculator workflow includes them)
• Maintenance-related inputs (if you’re modeling how maintenance may affect income concepts under RCW 26.09.090)

How outputs change when inputs change

Use these cause → effect rules to interpret the result you see:

Run scenarios, not just one number

A practical way to use a calculator is to compare multiple scenarios:

• Scenario A: current income and current parenting arrangement assumptions
• Scenario B: updated income for the next 6–12 months
• Scenario C: changed parenting-time assumptions
• Scenario D: with and without maintenance-related income changes

Because the core schedule is table-driven under RCW 26.19.020, even moderate changes to inputs can produce noticeable differences.

If you’re exploring other Washington family-law tools, you can browse additional DocketMath tools here: /tools.

Related reading

• How Alimony Child Support rules vary in New York — What varies by jurisdiction
• How to calculate Alimony Child Support in Philippines — Full how-to guide with jurisdiction-specific rules
• Worked example: Alimony Child Support in Philippines — Worked example with real statute citations