Generally speaking, child support is calculated by taking the gross income of the paying spouse (net resources) and multiplying that number by a certain percentage.  The percentage depends on the number of children involved.  However, there are numerous factors a court can consider in determining the amount of child support, and can deviate from the above formula. The parties are not required to follow the formula, and can agree on an amount which differs from the usual formula.  Child support obligations remain until the child turns 18 years of age, or graduates from high school, whichever is later.