Calculating Child Support

Child Support in Washington is calculated by a formula based solely on the net incomes of both parents. The court must follow this formula in all but extreme circumstances. However, no government formula is perfect or applicable to all situations.  A devious spouse can manipulate their taxable income and try to inflate yours. The inclusion of the cost for private schools, special lessons, and sports are not automatic. Educational expenses after high school can be a huge variable. The cost of children from prior and future relationships can defeat the formula.  All of these external factors must be considered and dealt with when setting a fair and reasonable support obligation. 

Child support laws in the state of Washington are designed to make sure the financial needs of the children are met.  Each parent has a legal duty to provide support.  In most cases, the children primarily reside with one parent.  The other parent then pays child support to the parent with whom the children live the majority of the time.  Even with 50/50 shared custody, the economically stronger parent will often be ordered to pay child support to the economically weaker parent.

Unfortunately, no automatic formula can consider all of the relevant facts. The schedule only works fairly when honest and accurate information is provided. It is up to the parties involved (and their lawyers) to make certain accurate income information is used, and compelling facts affecting child support payments are explained to the court. Income and expense information must be thoroughly discussed with your attorney.

Online Calculator

The Washington State Department of Social and Health Services provides an online Support Calculator. This resource can help you approximate your child support, but the projection is only as accurate as the information put into the formula. In certain special situations, the court can deviate from the state formula calculations. You will need to discuss any proposed deviation with your attorney and build your case appropriately.

Imputed Income

The court requires proof of income in order to determine child support. If the court does not receive adequate documentation, or if it believes a parent is intentionally unemployed or underemployed, the court can impute income. The court assigns an income level to that parent for the purpose of child support calculation regardless of the parent’s current actual income. It is important to supply all necessary income information to your attorney and to the court. If the court imputes income, that parent will pay more in child support.

If you are self-employed, own a business, or your income is commission based, it is important your income is correctly reported to the court. If your income is not properly documented and explained to the court you could end up paying more child support than required. An experienced Washington family law attorney can help you prepare the child support schedule and make sure your income is properly documented and reported.

Can Child Support be Changed?

Once an order of child support is issued by the court it can only be changed through a “modification”. This involves filing a petition to modify with the court and appearing at a hearing. A request for modification can be made after the support order has been in place for one year or if there has been “a substantial change in circumstances” such as changes in income or loss of employment.  The changing ages of the children will also change the amount of support. Find out more about Washington Divorce Modification.


Keep in mind the government takes child support enforcement very seriously. There are massive consequences to evading child support, enforceable by law. These include state and federal income tax offset, liens on real or personal property owned by the debtor, freezing of bank accounts, orders to withhold and deliver property to satisfy the debt, passport denial, or seizure and sale of property, with the proceeds from the sale applied to the support debt.

To read more on child support enforcement, the U.S. Department of Child Support Enforcement has provided this helpful PDF “Handbook on Child Support Enforcement”.

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