Most states have child support guidelines in their statutes—often in the statutes collected in the state’s family code. These child support guidelines provide percentages and methods of calculating child support payments based on the number of children; the parents’ incomes and financial resources; the income and needs of the custodial parent; the needs of the children, including any special needs; and the standard of living for the children before the parents’ divorce or separation. The child support guidelines are just guidelines, and the court generally has discretion to order more or less child support based on the best interest of the children.

In Missouri, child support guidelines are established by state statutes and are primarily found in the Missouri Revised Statutes, specifically in Chapter 452, which pertains to domestic relations and family law. These guidelines use an 'Income Shares Model' to calculate child support, which considers the combined income of both parents and allocates the responsibility for support in proportion to their respective incomes. The guidelines take into account the number of children, the financial needs and resources of both parents and children, including any special needs, and the standard of living the children would have enjoyed had the marriage not been dissolved. The Missouri courts use Form 14, which is a child support amount calculation worksheet, to assist in determining the presumed correct child support amount. However, the court has the discretion to deviate from these guidelines if it finds that the application of the guidelines would be unjust or inappropriate in a particular case, as long as it is in the best interests of the child. Factors that may lead to deviation include the financial needs and resources of the child and parents, the physical and emotional condition of the child, and the child's educational needs.