For individuals who want to know how to calculate child support to determine how much they will end up paying, there is no easy answer. Some states require individuals to pay a percentage of their pay each month. Others calculate it differently. Judges will take into consideration how much money an individual makes, how many children are involved in the case, whether or not the individual is currently paying any other court-ordered payments and more. However, in some states, individuals will end up paying roughly about one-fifth of their income for child support for one child. This is about 20%, and for each additional child, the amount will be raised 5%. This is dependent upon where the non-custodial parent lives, what judge oversees the case and more. In some cases, the individual may be required to pay more to cover extra medical care or if the individual makes more money than the average non-custodial parent. Anyone who must go to child support court should consider hiring a qualified attorney to represent them.