Washington Child Support Calculator

How Washington calculates child support

Washington sets child support with the Income Shares Model, and we have read the guideline that says so, which means both parents' incomes are combined, and each parent covers the share of the total obligation that matches their share of that combined income. Here is what that looks like in practice.

The Income Shares Model starts from an estimate of what the children would have received had the household stayed intact, then splits that figure between the parents. The calculation runs in three steps. Both parents' monthly incomes are added together. A basic support obligation for that combined figure and that number of children is set by the state's own guideline. Each parent is then responsible for the percentage of the obligation that matches their percentage of the combined income.

Because the obligation is divided by income share rather than assigned to one side, the receiving parent's earnings matter as much as the paying parent's. A parent bringing in 70 percent of the combined income carries roughly 70 percent of the total obligation. The parent the children live with most is treated as already spending their share through daily care, so only the other parent's share is ordered as a payment. That is why closing the income gap between two parents lowers the payment even when neither parent's own income falls.

Four things are then layered on top of the base figure: health insurance premiums covering the children, work-related childcare, support already being paid under an earlier order for other children, and, in most states, the number of overnights each parent has.

The figure Washington's own guideline works from is combined monthly net income, under RCW 26.19.071(5), applied to the RCW 26.19.020 economic table.

What moves the number in Washington

• Both parents' monthly incomes, and the gap between them
• Number of children covered by the order
• Health insurance premiums covering the children
• Work-related childcare paid for the children
• Support already ordered for children from another relationship

Income limits and judicial discretion

Washington puts a figure at the top of its Economic Table and the statute is explicit that it is not a limit. RCW 26.19.065(3) makes the table "presumptive for combined monthly net incomes up to and including $50,000" and says that above it "the court may exceed the presumptive amount" on written findings of fact. The discretion runs upward only, so the top row is a floor and this page presents it as one. Two things about the number itself. It is stated at combined NET income rather than gross, and this calculator collects gross, so we reach the line earlier than the statute does. And until Phase Y this site carried Washington as a cap at $12,500 of one parent's gross income, which was the wrong figure, the wrong income basis and the wrong mechanism all at once. Washington gives judges a moderate amount of room on custody and parenting time, so expect the order to start from the guideline figure and move with the facts of the case.

Washington child support examples

These three examples run through the same Washington calculator on this page, so the figures match what the tool returns for the same entries. Each example changes one thing against the one before it, so you can see which lever moved the result. All three assume a standard schedule of 80 overnights a year with the paying parent, though the overnight count does not change the Washington guideline figure either way.

Comparing the first two examples shows what a second child is worth in Washington: the order moves from $794 to $1,200a month on identical incomes. The third example raises the paying parent's earnings and adds health insurance and childcare, which are credited back against the obligation rather than added on top of it.

Where parenting time fits in Washington child support

Washington is one of the states where the answer is: it does not. Guideline support here does not change with the number of overnights. Run the same family through the Washington guideline at 52 nights a year and again at equal time, and the figure is identical, because overnights are not one of the guideline's inputs. The calculation runs on income, the number of children before the court, and other children a parent already supports. The controlling authority is RCW 26.19.020.

Time with the children still reaches support, just not inside the formula. RCW 26.19.075(1)(d) makes "the child spends a significant amount of time with the parent who is obligated to make a support transfer payment" a ground on which a court may depart from the standard calculation, and where the guideline figure itself is not at stake a departure can move the order in either direction. That is a judgment made on the facts of a particular case, not a credit that switches on at a set number of nights. The trigger has no number attached to it anywhere in the statute: no overnight count, no percentage of the year. If you expect to have the children a substantial share of the year and you want that reflected in the order, it is an argument to make to the court, not an adjustment the guideline makes for you.

And in Washington the argument is not always available to make. RCW 26.19.075(1)(d) bars the deviation outright, in the statute's own words, if "the deviation will result in insufficient funds in the household receiving the support to meet the basic needs of the child", or if "the child is receiving temporary assistance for needy families". Two independent bars, either one enough on its own. That is a real difference from a state that simply leaves the question to a judge: here a reduction is not merely uncertain, it is off the table for a whole class of cases however much residential time the paying parent has. A 2023 Washington appellate decision upheld the denial of a residential deviation to a father with equal residential time and roughly three times the mother's income, on the ground that a deviation would leave her household without enough to meet the child's basic needs. Equal time, higher earner, denied. Anything you read that says a 50/50 schedule reduces Washington support is describing an outcome the statute permits, not one it produces.

Where Washington starts on parenting time

Washington does not presume equal parenting time. That is our own record rather than Washington's own custody law. Courts set the schedule on the best interests of the children, and that schedule governs where the children actually are, which nights each parent covers, and how holidays are split. What it does not do is feed the guideline calculation, which is why two Washington families with identical incomes and very different schedules arrive at the same guideline figure.

Getting a child support order in Washington

The guideline figure is only half the picture. When the order actually arrives, and what it costs to argue about it, vary quite a bit from state to state, and both shape what a family lives on in the meantime.

Residency required

No minimum

Waiting period

3 months

Typical uncontested

4 months

Typical contested

about 1.2 years

Support before the case is finished

Washington sets no minimum residency before filing, and a statutory period of 3 months has to run before a judge can finalize the divorce. States measure that period from different starting points, some from filing, some from service on your spouse, and some from the date the two of you separated, so confirm where Washington's clock begins. A contested case in Washington runs about 1.2 years on average, against 4 months when the parents agree. That gap is why temporary support matters. A judge can enter a temporary order early in the case, calculated on the same guideline, so the children are covered while the rest of the case is worked out. If money is tight now, a temporary order is usually the fastest relief available, and waiting for the final judgment can mean months without support.

What it costs to contest the number

Family law attorneys in Washington typically run $275 to $500 an hour, and mediation costs roughly $300a session. Worth doing the arithmetic before digging in: a handful of billable hours on each side can cost more than a full year of the amount being argued over. Where the disagreement is genuinely large, or where one parent's income is hard to pin down, representation earns its keep. Where the gap between the two positions is a few dozen dollars a month, mediation or a negotiated agreement almost always leaves both households better off. Our record carries collaborative divorce as available in all fifty states, so it says nothing specific about Washington; whether trained collaborative attorneys practise near you is a local question. Where it is on offer, both parents commit in writing to settle without litigation and use shared financial experts rather than competing ones.

Changing or enforcing a Washington order

Modifying an existing order

A child support order is not permanent, but it also does not adjust on its own. Either parent can ask the court to recalculate, and the general standard across states is a substantial and continuing change in circumstances since the last order. Job loss, a significant raise, a change in the parenting schedule, a new child support obligation for another child, and a change in the children's medical or childcare costs are the changes that most often qualify.

Two points catch parents out. The first is that a modification usually takes effect from the date the request is filed, not the date the circumstances changed, so waiting to file means absorbing the gap. The second is that the obligation continues in full until a judge signs a new order. An informal agreement between parents to pay less does not bind the court, and arrears can still accrue against the paying parent for the difference.

Enforcement

Enforcement runs through Washington's child support agency as well as the courts. Federal law requires every state to run a child support enforcement program with a common set of tools, which is why the remedies look broadly similar from state to state: income withholding straight from wages, interception of federal and state tax refunds, reporting to credit bureaus, suspension of driver's and professional licenses, liens against property, and contempt proceedings for willful non-payment. Income withholding is the default for new orders in most cases rather than a penalty applied after a missed payment.

Washington guideline authority and official worksheet

Washington carries its child support guideline across more than one instrument, and all of them are in our data:

• RCW 26.19.020
• RCW 26.19.065
• RCW 26.19.080

Those authorities control, and the worksheet published under them is the document a court works from. The estimate on this page models the guideline, it does not replace the worksheet.

Where to get the official worksheet

Every state publishes a child support worksheet or an official calculator, and that document is what a judge or the state agency works from. We do not yet have a verified direct link to Washington's worksheet, so the starting points below are the state's own court site and the federal directory of state child support agencies rather than a deep link we cannot vouch for.

• Washington courts , the state judiciary site from our Washington source record.
• Office of Child Support Services, U.S. Administration for Children and Families, which maintains the directory of state child support agencies.
• National Conference of State Legislatures, child support guideline models by state, which publishes its own comparison of the guideline model each state uses, so you can check ours against it.

How we calculate this estimate

We apply the guideline model your state actually uses, and the models differ more than most summaries suggest. Most states follow the Income Shares Model: both parents' monthly incomes are combined, a basic support obligation is drawn from that combined figure and the number of children, and each parent covers the share that matches their portion of the combined income. Which income figure gets combined is the state's own to define and it is not the same one everywhere, so this page names it for your state where the guideline has been read and does not guess at it where it has not. Percentage of Income states apply a set rate to the paying parent's income alone, and Nevada's tiered version steps that rate down across income brackets. The Melson Formula reserves a self-support amount for each parent before dividing what is left. Some states do neither: North Dakota reads a dollar figure off a table keyed to one parent's net income, and California publishes a single algebraic formula with no schedule behind it. Which one your state is on is named on its own page rather than inferred from a list here. Credits for health insurance and childcare are applied where the state's own guideline builds them into the order, along with any income cap the state sets, and the list of what moves the number on each state's page names the levers that actually move that state's figure. Parenting time is computed in the states whose own guideline we have read and implemented, and in no others.

What the estimate assumes for Washington

• Income figures are gross monthly, before taxes, counting the sources your state includes.
• Parenting time moves the figure only where we have read and implemented the state's own rule. The parenting-time section further down this page says which case this state is in, and where no adjustment applies the estimate is the amount before one. We previously reduced support past 146 overnights on a coefficient of our own. 146 turned out to be a single state's statutory threshold applied to all fifty, the size of the reduction had no legal source anywhere, and the mechanisms states actually use are not variations on one rule. Among the ones we have now read: a worksheet that switches at a threshold both parents must clear, an offset applied continuously with no trigger, a threshold that does nothing below it and slides above it, a term written into the guideline formula itself so there is no unadjusted amount at all, no parenting-time term anywhere, and a formula prescribed by statute whose text we do not have. That list is what we have read rather than what exists, and it has grown with every state checked. We removed ours rather than defaulting it, and we publish each state's adjustment as that state's own rule is verified.
• North Carolina is one of the verified threshold cases, at 123 overnights under the guidelines adopted pursuant to N.C. Gen. Stat. 50-13.4(c1). The threshold has to be cleared by both parents, which is why a parent well past an even split can fall outside shared care entirely.
• Texas has no parenting-time adjustment at all, because its guideline has none. Tex. Fam. Code 154.125 runs on the obligor's net resources and the number of children, and the state's own calculator has no field for overnights. Possession time enters only as a discretionary deviation factor, Tex. Fam. Code 154.123(b)(4).
• Georgia has a mandatory parenting-time adjustment whose formula we do not have. O.C.G.A. 19-6-15(g), effective January 1 2026, requires the court to adjust the noncustodial parent's basic obligation wherever there is a court-ordered parenting time schedule, with the result entered on Child Support Schedule C. Applying arithmetic of our own in place of a prescribed formula would be worse than applying none, so the Georgia estimate is the presumptive amount before that adjustment.
• Where a state's own schedule has been transcribed, the basic obligation is read straight off it. Where it has not, the figure comes from a national approximation of the tables courts read from, and the source panel on that state's page says which of the two you are looking at. That approximation has been measured against the seven transcribed schedules keyed to the same thing it is, at 546 income and family-size combinations. It missed them by 32 to 86 percent on average, and it missed them in both directions at once: at every income from $1,500 to $6,000 of combined monthly income it came in under at least one of those schedules and over another, then above all seven from $8,000 up, reaching 69 to 240 percent above those states' own tables at $30,000. So a modeled figure at a high combined income is the least reliable number this calculator returns, and near $6,000 is where the approximation lands closest.
• Where a state sets an income ceiling, we clamp income at it. That is a fair model of a real cap and a poor one of everything else, so two states are handled differently. New York's $193,000 of combined parental income is the point above which a court may consider the additional income, not a limit on what it can order, and our figure there is the amount the guideline produces at the threshold. New Jersey's Appendix IX-F schedule ends at $3,600 of combined weekly net income, and courts are instructed in capital letters not to extrapolate past it, so we read the obligation at the schedule's last row and treat the result as the minimum basic support award rather than as a guideline amount. Appendix IX-A requires a New Jersey court to add to that minimum from the income above the ceiling. Modeling what a court adds is not something we can do honestly, because it turns on statutory factors rather than on arithmetic. Above the New Jersey line our figure is therefore a floor, and above the New York line it is not one: the addition New Jersey requires is what makes its schedule figure a minimum, and no New York instrument says an award may not come in below the amount at the threshold. Both figures read as the low end of a realistic range and only one of them is a floor a reader can count on.
• The same schedule can also stop short at the bottom. New Jersey publishes no award figure below $180 of combined weekly net income, where the court sets the amount from the paying parent's income and living expenses within a published range. Our estimate at that income is a modeled figure with nothing from the state to check it against, and it says so.
• The result is a guideline number. Judges can deviate from it when the facts justify a different amount.

Where the estimate stops

Your state's official worksheet is the controlling document, and a court order can land somewhere other than any guideline estimate. Use this to prepare, then confirm the figure with a licensed family law attorney or your state's child support agency.

Read the full methodology for how every calculator on the site is built.

Sources

Washington courts and statutes

• courts.wa.gov
• RCW 36.18.020 ($254 statutory base + dissolution; King County total ~$314)
• RCW 26.19.020
• RCW 26.19.065
• RCW 26.19.071
• RCW 26.19.080
• RCW 26.19.075(1)(d)

Where to read more

Background reading, not where the figures above came from. No number on this page is taken from any of these.

• National Conference of State Legislatures, child support guideline models by state
• Office of Child Support Services, U.S. Administration for Children and Families
• American Bar Association, Section of Family Law

About this page

Written by Barron Hansen

I am an app developer who is dedicated to building the highest-value, most accurate web apps possible, that people want to use every day.