Like other states, Texas uses an established formula to determine how much a parent must pay in child support. In order to apply this formula, Texas courts use the Texas Child Support Guidelines.
The point of these guidelines is to make sure that courts order child support in a consistent fashion. Doing so prevents parents from feeling a sense of unfairness in the event where one court orders a parent to pay a much higher or lower amount than what a parent in the same situation was ordered to pay the next county over. Consistency also helps parents make appropriate plans for how much support they will receive or pay.
Basically, the guidelines require a court to look at each parent's income. Income naturally includes one's wages or salary, but it can include other things as well, even monetary benefits that one might not typically think of as income.
After doing so, the court will make certain deductions in each party's income and then take in to account other considerations, like which parent is providing health insurance and how much time each parent is spending with their children. The guidelines will ultimately aid the court in determining the correct amount of support to apportion to each parent.
While they are applied formulaically, child support guidelines do not end all disputes between couples over the correct amount of support. There can be disputes about how much income each parent truly makes or is capable of making. Moreover, some families face special circumstances that make a strict application of the support guidelines inappropriate for their case, and one parent may as a result ask for a higher or lower amount of support.