A child support calculator can help an individual determine about how much child support they would be required to pay each month by a court of law. Typically, these calculators work differently for each different state, because the laws and rules are different. However, an individual will put in the number of children he or she has that are living with the custodial parent, the amount of money they make each month from their job, the number of children they may already pay child support for who may belong to another custodial parent - and then they receive the amount that is an estimate of what they would be ordered to pay by the court. While many of these child support calculators may come very close to the real amount one would pay, it's important to speak to a child support attorney to get an accurate amount based on the state laws and circumstances of the case.