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Calculating Child Support

Divorce is almost always challenging and emotional—even more so when there are children from the marriage. Common issues that come up in divorces involving children include child custody and child support.

Understanding how child support is calculated is important so parents understand their obligations. If you have questions about calculating child support, speak to a family law attorney in Phoenix for assistance.

Arizona Uses an Income-Shares Model

The state of Arizona uses an income-shares model when determining child support. This means that each parent must provide a proportionate amount of their income. Typically, the court will require the parent who does not have custody to provide a percentage of their gross monthly earnings to the custodial parent for child support.

The court will consider how much money would have been spent on child care to determine the amount of child support the custodial parent receives. Based on this amount of money and the following factors, the court will calculate child support:

  • Gross income for each parent
  • How much time does each parent care for the child in a year
  • Cost of childcare
  • Additional educational expenses
  • Health insurance
  • The number of children from the marriage
  • Other care costs for a child with special needs

“Gross Income” Is Broadly Interpreted

Arizona child support laws state that gross income is inclusive and interpreted broadly. This means that the parent must disclose their wages, stock investment interest, bank accounts, investment accounts, awards and prizes, commissions, bonuses, government benefits, workers’ comp benefits, insurance benefits, annuities, and pensions.


Just about any revenue source is used to determine a parent’s gross monthly income. The amount of child support will vary and is up to the judge’s discretion based on the income-shares model.

Judge May Impute Income For Unemployed Parent

Note that if the judge thinks that a parent is purposely unemployed or under-employed, they can estimate the income based on that parent’s earning potential. For example, if the parent is a plumber but is continually unemployed, the judge may blame the parent’s income by determining the typical wage for plumbers in the community.

Child Support Obligations Come First

The guidelines state that child support takes precedence over all other financial obligations. This statement includes supporting your own parents or stepchildren. This is the case because state law says that parents are legally obligated to support their biological and adopted children.

Parents should not assume that there is no child support payment if they share equal custody of the children. Both parents are responsible for supporting their children, and there is usually one payment to the other for child support. An exception is that if the parents earn similar incomes and spend the same amount of time with the child. That is not likely to happen, however.

In most cases, the custodial parent receives child support from the other parent. However, in rare cases, the judge may order the custodial parent to provide child support.

The court will set a termination date when one parent can no longer pay child support. Child support usually terminates on the last day of the month when the youngest child turns 18. If the divorce court determines that the youngest child won’t finish high school by turning 18, support will end on the late day of the month when the child graduates or turns 19.


The divorce court also may order continued child support beyond the child’s 18th birthday. This would only be if the child has a significant physical or mental disability that affects their ability to live on their own.


Calculating child support can be tricky and hard to understand under the income-shares model used in Arizona. Talk to a child support attorney if you have questions.