Child support laws in Washington are designed to ensure that a child’s financial needs are met and that both parents are adhering to their legal duty to provide support.  The amount of support is set by law and determined using the Child Support Schedule. The Basic Support Obligation is calculated based on the combined monthly net income of each parent and the number and ages of the children. Generally, the parent with whom the children spend the majority of their time receives support, and the higher-earning parent pays support.  Unfortunately, no automatic formula can consider all of the relevant facts. The Schedule only works fairly when honest and accurate information is provided by the parents. It is up to the parties involved (and their lawyers) to make certain that accurate income information is used and that 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 that is put into the formula. In certain special situations, the court can deviate from the state formula calculations. You’ll need to discuss any proposed deviation with your attorney and build your case appropriately.