Child support in Washington is set up with a calculation. The calculation is worked out by the legislature every few years. Everyone - all parents - will pay the child support that the math calculations set for the individual parent's income level. The calculation leaves 45% of the parent's net income for the parent. To get to the number, both parents' income is added together to get a total number for support that is owed to the child or children. Then each individual parent pays their proportionate share of that total, based on the parent's income relative to each other. The parent with the higher income pays a transfer payment to the parent with the lower income, in order to keep things as equal as possible.
Both parents owe support to the children. And support is not intended to cover only some specific expenses. The support is meant to keep the children as comfortable as they could normally expect to be with a family of similar income. There isn't a list of expenses that are required for child support. Both parents are expected to pay the children's needs, and wants, in a way that keeps the children comfortable.
Most parents worry that their support payment will be either too high (for the parent paying) or too low (for the parent living on the support). Adjustments and deviations are available - and usually very easy to arrange with an agreement.
Child support calculations can be complicated. We're happy to work out your calculation, based on your income.