While the percentages differ from state to state, the guidelines apply a percentage to the payor's income. The child support can be expressed as a floating percentage of income or as a fixed dollar amount. Usually, the parent without the child the majority of the time will pay support, but if both parents share time with the child equally, the parent with the greater income usually pays support. The support may be reduced based upon the amount of time the payor spends with the child. Some states also cap support at a certain income level.
States vary on what expenses are included in child support.
For example, some states include medical expenses and day care, while others states add those costs on top of the child support.