First, the payments are based on what the noncustodial parent earns. The formula has been set by the Supreme Court on Civ. Rule 90.3. That rule says that the noncustodial parent of one child is expected to pay 20% of the adjusted income to support one child. Adjusted income means earnings after deductions for taxes, union dues, retirement deductions, and other mandatory deductions. For example, if the noncustodial parent`s adjusted income is $1,000.00 per month and that parent has one child, the monthly support obligation would be $200.00. If there are two children, the percentage of adjusted income for child support would increase to 27%. For three children the obligation percentage would increase to 33% and it would continue to increase by 3% per child thereafter. Civil Rule 90.3 also takes into account shared custody, visitation and, in some cases, exceptional circumstances, such as divided custody, to allow for deviation from the rule. Deviations are very rare.