What Arizona Child Support Costs for One Child

Arizona does not set a fixed dollar amount for child support — the court calculates it based on each parent's income, custody arrangement, and other factors

Arizona uses a income shares model, which means the court adds both parents' incomes together, finds what percentage of combined income goes to child support under state guidelines, then splits that obligation between parents based on how much each earns. A parent with one child might pay anywhere from under $200 per month to over $1,000 per month depending on their income and the other parent's income. The only way to know what you or the other parent would owe is to run the numbers through Arizona's formula.

The court also considers who has physical custody (the child lives with them most of the time) and who has legal custody (the right to make decisions about school, medical care, religion). If one parent has the child most of the time, the other parent typically pays support. If custody is split roughly equally, the higher-earning parent usually still pays, but the amount is lower.

Key Takeaways

• Arizona calculates child support by combining both parents' incomes, explore a percentage from state guidelines, and dividing the result based on each parent's share of income.
• The same income level produces different support amounts depending on custody arrangement — sole custody orders result in higher payments than shared custody.
• Income includes wages, self-employment earnings, bonuses, rental income, and some benefits; it does not include child support or spousal support the parent receives from someone else.
• Arizona courts can adjust the guideline amount if following it would be unjust or if the parents agree to a different amount in writing.
• Child support continues until the child turns 18 or graduates from high school, whichever is later, unless the child is still in school after turning 18.

How Arizona's income shares formula works

Start with the combined monthly income of both parents. Arizona's guidelines set a percentage of that combined income that goes toward child support. For one child, that percentage is roughly 17 percent of combined income, though the exact percentage can shift slightly depending on how many children are involved and the specific circumstances.

Once you know the total support obligation, the court divides it between parents based on their income split. If one parent earns $3,000 per month and the other earns $2,000 per month, the first parent pays 60 percent of the obligation and the second pays 40 percent. The parent who does not have primary physical custody usually pays their share to the parent who does.

The court also subtracts certain costs from income before calculating support — mainly childcare expenses needed so a parent can work, health insurance premiums for the child, and uninsured medical costs the parents have already paid. These deductions lower the income used in the formula, which lowers the support amount.

What counts as income for child support in Arizona

Income includes W-2 wages, self-employment earnings, bonuses, commissions, rental income, interest and dividend income, and income from pensions or retirement accounts. It also includes unemployment benefits and some types of disability payments. The court looks at the most recent tax return and recent pay stubs to verify income.

Income does not include child support or spousal support the parent receives from someone else, or Supplemental Security Income (SSI). If a parent is voluntarily unemployed or underemployed — meaning they could earn more but choose not to — the court may assign them "imputed income" based on what they could reasonably earn. This prevents a parent from lowering support by quitting a job.

If a parent's income changes significantly — a job loss, a raise, a promotion — either parent can ask the court to modify the support order. The change usually has to be substantial and ongoing, not temporary.

How custody arrangement affects the support amount

If one parent has the child 70 percent of the time and the other has the child 30 percent, the parent with less time pays support. The calculation is the same — combined income, guideline percentage, split by income share — but the parent with more custody receives the payment.

If custody is split 50-50, both parents still have income-based obligations, but the parent who earns more pays the difference to the parent who earns less. For example, if the guideline amount is $400 per month and one parent's share is $240 while the other parent's share is $160, the first parent pays $80 to the second.

Custody for child support purposes is based on where the child physically lives, not on legal decision-making authority. A parent can have the right to make school and medical decisions but still pay support if the child lives with the other parent most of the time.

When Arizona courts adjust the guideline amount

Arizona law allows courts to order a different amount than the guidelines produce if following the guidelines would be unjust or inappropriate. Reasons include one parent having significant assets or income beyond what the formula captures, a child with special needs requiring extra expenses, or a parent's other support obligations to children from different relationships.

Parents can also agree in writing to a different amount. The court will approve a written agreement as long as it is not obviously unfair to the child. Many parents negotiate a support amount outside court and then ask the judge to sign off on it, which is faster and cheaper than having the court calculate it.

If the court orders a different amount than the guidelines suggest, the order must explain why in writing. This explanation matters later if either parent wants to modify the order — the court needs to know whether the deviation was intentional or based on circumstances that have since changed.

How to estimate your child support obligation

You can use Arizona's child support calculator, which is available on the Arizona Department of Child Support Services website. Enter both parents' gross monthly income, the custody arrangement, childcare costs, and health insurance costs. The calculator shows what the guideline amount would be.

The calculator is a starting point, not a legal information. It does not account for all the factors a court might consider, and it assumes you have entered income correctly. If you are preparing for a court hearing or negotiating with the other parent, consider working with a family law attorney or a mediator who can review your specific situation.

Keep in mind that the amount shown is what the guidelines suggest — the actual court order could be different if the judge finds the guideline amount unjust or if both parents agree to something else.

What happens if a parent does not pay

Arizona's Department of Child Support Services can enforce a support order through wage garnishment (taking money directly from a paycheck), intercepting tax refunds, placing a lien on property, or suspending a driver's license. If a parent falls behind on payments, the other parent can also ask the court to hold them in contempt, which can result in fines or jail time.

If the paying parent's income drops — due to job loss or a medical issue — they should ask the court to modify the order rather than straightforward stop paying. Continuing to pay under the old order while requesting a modification shows good faith and can affect how a judge handles the case.

Frequently Asked Questions

Does Arizona child support change when the child turns 18?

Child support continues until the child turns 18 or graduates from high school, whichever is later. If the child is still in high school after turning 18, support continues until graduation or age 19, whichever comes first. Once the child is no longer in school and is 18 or older, the obligation ends unless the court has ordered otherwise.

Can I modify the child support order if my income changes?

Yes. Either parent can ask the court to modify the order if income has changed by at least 10 percent or if there has been a substantial and ongoing change in circumstances. You will need to file a petition with the court and provide recent pay stubs or tax returns showing the change. The modification is effective from the date you file, not retroactively.

What if the other parent is self-employed or has irregular income?

The court uses tax returns and business records to determine self-employment income. If income is irregular, the court may average it over a period of time or use the most recent year's tax return. If a self-employed parent's income is hard to verify, the court may impute income based on similar work in the area or require the parent to provide detailed financial records.

Does child support change if custody changes?

Yes. If the custody arrangement changes — for example, the child moves to live with the other parent — either parent can ask the court to modify the support order. The new order is calculated using the same formula but with the new custody percentages. Changes in custody are one of the most common reasons for modifying support.

Can parents agree to a different child support amount without going to court?

Yes, but the agreement must be in writing and signed by both parents. You can then ask the court to approve it as part of a divorce decree or a separate child support order. The court will review it to make sure it is not obviously unfair to the child, but if both parents agree and the amount is reasonable, the court will usually approve it.