Child Support in Arizona: Guidelines and Calculations

A father in Mesa with two children — ages 8 and 14 — was surprised when his child support obligation was higher than he expected. He assumed the calculation would simply take his income, apply a percentage, and produce a number. What he did not anticipate: Arizona’s Income Shares Model uses both parents’ combined incomes, applies a basic support obligation from a statutory table, adds an automatic 10% increase for his 14-year-old, factors in health insurance and childcare costs, and then adjusts the total based on his parenting time schedule. The 10% older child adjustment alone — which applies to any child age 12 or older — added approximately $130 per month to his obligation. The parenting time adjustment, based on the exact number of days he had the children, reduced his obligation by a different amount. The final number was the product of multiple calculations, not a simple formula.

Understanding how Arizona calculates child support helps you plan financially and negotiate effectively. This guide covers the current guidelines under A.R.S. Section 25-320, the step-by-step calculation process, how parenting time affects the amount, and the rules for modification and enforcement. For a national overview, see our guide on child custody laws explained, and try our child support calculator for a quick estimate.

How Arizona Calculates Child Support

Arizona uses the Income Shares Model, the same framework used by approximately 40 states. The principle: children should receive the same proportion of parental income they would have received if the family remained intact.

The current Arizona Child Support Guidelines became effective January 1, 2022, adopted by the Arizona Supreme Court through administrative order. The guidelines are reviewed at least once every four years as required by state and federal law.

Step-by-Step Calculation

Step 1: Determine each parent’s gross monthly income. Arizona defines gross income broadly, including income from all sources:

• Wages, salaries, commissions, bonuses, tips, overtime
• Self-employment income (gross revenue minus ordinary and necessary business expenses)
• Rental income, dividends, interest, capital gains
• Pensions, retirement benefits, annuities
• Social Security benefits, workers’ compensation, unemployment benefits
• Spousal maintenance received
• Severance pay and recurring gifts

Step 2: Apply adjustments to gross income. Each parent’s gross income is adjusted by subtracting:

• Court-ordered spousal maintenance paid to a former spouse from another relationship
• Support obligations for children from other relationships
• Other permitted adjustments

The result is each parent’s Adjusted Gross Income.

Step 3: Combine both parents’ adjusted incomes. The combined Adjusted Gross Income determines where the case falls on the Schedule of Basic Support Obligations. The 2022 guidelines cover combined incomes up to $30,000 per month (expanded from $20,000 in the previous guidelines).

Step 4: Find the basic support obligation. Using the schedule, look up the combined adjusted income and the number of children. The table provides the total monthly basic support obligation.

Step 5: Apply the older child adjustment. If any child is age 12 or older, the basic support obligation allocated for that child is increased by 10%. This reflects the higher cost of raising older children.

Step 6: Add additional expenses. Health insurance premiums for the children, work-related childcare costs, extraordinary education expenses, and extraordinary medical expenses are added to the basic obligation.

Step 7: Calculate each parent’s proportionate share. Divide each parent’s Adjusted Gross Income by the combined total to determine their percentage. Apply that percentage to the total child support obligation.

Step 8: Apply the parenting time adjustment. Arizona adjusts the obligation based on how many days each parent has the child per year. The non-custodial parent’s share is reduced by a percentage corresponding to their parenting time (see the parenting time adjustment table below).

Step 9: Apply credits. The parent who pays health insurance premiums or childcare costs directly receives a credit against their obligation.

What Counts as Income (and What Doesn’t)

Arizona’s definition of gross income is broad but has limits.

Included:

• All employment income (wages, salary, bonuses, commissions, tips, overtime)
• Self-employment earnings (gross revenue minus ordinary and necessary business expenses)
• Investment income (dividends, interest, capital gains, rental income)
• Government benefits (Social Security, workers’ compensation, unemployment)
• Retirement income (pensions, annuities)
• Spousal maintenance received
• Severance pay and recurring gifts
• Non-cash benefits (assigned a cash value)

Not included:

• Child support received for children from another relationship
• Means-tested public assistance (TANF, SNAP, SSI)
• Reimbursements or expense allowances that do not significantly reduce living expenses

Self-Employment Income

Self-employed parents receive special scrutiny. The court uses gross revenue minus ordinary and necessary business expenses — not the net income reported on tax returns. Business expenses that reduce personal living expenses (such as a car payment or phone bill paid by the business) are counted as income. Documentation required includes tax returns (Schedules C, E, F), profit and loss statements, and bank statements.

Imputed Income

If a parent is voluntarily unemployed or underemployed, the court may impute income — attributing earning capacity based on education, work history, skills, job market conditions, age, health, and prior earnings. Minimum imputed income is Arizona’s current minimum wage.

Exceptions: income is generally not imputed to a parent attending education or training to improve earning capacity, a parent whose child’s needs require them to stay home, or a parent receiving cash assistance benefits.

How Parenting Time Affects Support

Arizona’s parenting time adjustment is detailed and specific, based on the exact number of days each parent has the child.

How Days Are Counted

The guidelines define parenting time days as follows:

• 12+ hours = 1 full day
• 6-11 hours = 0.5 day
• 3-5 hours = 0.25 day
• Less than 3 hours = 0.25 day only if the parent covers child-related costs (meals, etc.)

Time the child spends in school or daycare does not count toward a parent’s parenting time.

Parenting Time Adjustment Table

The non-custodial parent’s support obligation is reduced based on their parenting days per year:

Equal Parenting Time

When parenting time is divided equally (approximately 182.5 days each), the adjustment can substantially reduce or eliminate the support obligation — depending on the income differential. With truly equal time, equal expenses, and equal incomes, no support obligation exists. When incomes differ, the higher-earning parent typically pays a reduced amount to the lower-earning parent.

Healthcare and Childcare Costs

Health Insurance

At least one parent is required to provide health insurance for the children when available at a reasonable rate. The cost of the children’s health insurance premium is:

• Added to the basic support obligation
• Shared proportionally between parents based on income shares
• Credited to the parent who pays the premium directly

Uninsured medical, dental, and orthodontic expenses not covered by insurance are also allocated proportionally between parents.

Childcare Costs

Work-related childcare costs are included in the calculation when:

• The childcare is provided by a non-dependent care provider
• The cost is incurred so a parent can work or seek employment
• The amount is appropriate to the family’s financial situation

Childcare costs are annualized and divided by 12 for a monthly figure, then added to the basic obligation and shared proportionally.

The Older Child Adjustment

One of the more distinctive features of Arizona’s guidelines is the 10% older child adjustment. When a child is age 12 or older, the basic support obligation allocated for that child is automatically increased by 10%. This reflects research showing that older children cost more to raise — larger appetites, more expensive clothing, extracurricular activities, technology needs, and transportation costs.

For families with children of different ages, this means the support amount is higher for the older children and lower for the younger ones, even within the same case.

When Courts Deviate from the Guidelines

The court may deviate from the guideline amount when strict application would be inappropriate or unjust. Under A.R.S. Section 25-320, deviation factors include:

• Financial resources and needs of the child
• Financial resources and needs of each parent
• The standard of living the child would have enjoyed in an intact household
• Physical and emotional condition of the child and educational needs
• Significant disparity of income when each parent has significant parenting time
• Combined income exceeding $30,000 per month
• Significant travel expenses related to parenting time
• Unusual emotional or physical needs requiring a parent’s presence

The court must provide written findings explaining why deviation serves the child’s best interests and must state what the guideline amount would have been.

Modifying Child Support

Arizona child support orders can be modified when circumstances change under A.R.S. Section 25-327.

Substantial and Continuing Change

Either parent may petition for modification by demonstrating a change that is substantial and continuing. A change is presumptively substantial if the recalculated support amount differs from the current order by 15% or more.

Common qualifying changes include:

• Significant and continuing change in income (job loss, disability, new employment)
• Change in parenting time arrangements
• Change in the number of children in the household
• Addition or loss of health insurance coverage
• Incarceration following criminal conviction

Effective Date

Modifications are effective from the date the motion is filed — they cannot be retroactive. Past-due amounts (arrearages) that accrued before the motion was filed cannot be modified or forgiven. File promptly when your circumstances change.

When Child Support Ends

Under A.R.S. Section 25-501, child support terminates on the last day of the month in which the child turns 18 years old.

Exception: If the child is still enrolled in and attending high school when they turn 18, support continues until the child graduates or turns 19, whichever occurs first.

Other termination events include the child’s marriage, emancipation by court order, entry into active military duty, or death.

Arizona does not allow courts to order parents to contribute to post-secondary education expenses. This contrasts with states like Washington, where courts can order college support.

Enforcement

Arizona’s Division of Child Support Services (DCSS) within the Department of Economic Security enforces child support orders through multiple mechanisms:

• Income withholding — the default method; support is deducted directly from wages
• Tax refund interception — federal and state refunds redirected to cover arrears
• Bank account seizure — funds withdrawn directly to cover arrears
• Property liens — placed on real estate, vehicles, and other assets; must be satisfied before selling or refinancing
• License suspension — driver’s, professional, and recreational licenses suspended when a parent owes six or more months of past-due support
• Passport denial — for arrears exceeding $2,500 under federal law
• Credit bureau reporting — delinquent support reported to credit agencies
• Contempt of court — available once a parent is 30 days behind; may result in fines or jail time
• Criminal prosecution — failure to pay is a Class 6 felony in Arizona; first-time offenders face four months to two years in prison

Interest on Arrears

Unpaid child support accrues simple interest at 10% per year under A.R.S. Section 25-510, beginning at the end of the month following the month the payment was due. Interest accrues only on principal, not on previously accrued interest.

Frequently Asked Questions

How much is child support in Arizona for one child?

It depends on both parents’ combined adjusted gross incomes and the parenting time schedule. As a rough example, for combined adjusted gross income of $8,000 per month with one child under age 12 and a standard parenting time arrangement, the basic monthly obligation is approximately $1,100 to $1,300 before adjustments for health insurance and childcare. Use our child support calculator for an estimate based on your numbers.

Does child support end at 18 in Arizona?

Usually, yes. Child support ends on the last day of the month in which the child turns 18. If the child is still in high school at 18, support continues until graduation or age 19, whichever comes first. Arizona does not allow courts to order parents to pay for college.

How does equal parenting time affect child support in Arizona?

Equal parenting time (approximately 182.5 days each) significantly reduces the support obligation through the parenting time adjustment. However, equal time does not automatically eliminate support. If one parent earns significantly more than the other, a transfer payment may still be ordered so the child has a comparable standard of living in both homes.

What is the 10% older child adjustment?

Arizona automatically increases the basic support obligation by 10% for any child age 12 or older. This reflects the higher cost of raising older children. For families with children of different ages, the older children have a higher support allocation than younger siblings in the same case.

Can child support be modified if I lose my job?

Yes, if the job loss constitutes a substantial and continuing change in circumstances. A change is presumptively substantial if the recalculated amount differs from the current order by 15% or more. File a motion promptly — modifications are effective from the filing date, not retroactively. If you voluntarily quit or reduce your hours, the court may impute income based on your earning capacity.

How This Guide Was Researched

This guide was created by reviewing publicly available legal information from official state statutes, judiciary websites, court resources, and family law publications. The goal is to explain family law topics in plain English so readers can better understand the process before speaking with an attorney.

Sources and Legal References

This guide is based on publicly available legal information and official sources, including:

• A.R.S. 25-320 — Child Support Guidelines
• A.R.S. 25-327 — Modification of Support
• A.R.S. 25-501 — Duty of Support
• A.R.S. 25-510 — Interest on Arrearages
• 2022 Arizona Child Support Guidelines (PDF)
• Arizona Courts — Child Support Information

Official Arizona Resources

• Arizona Division of Child Support Services
• Arizona Judicial Branch — Self-Service Center
• Maricopa County Superior Court — Family Court
• Arizona Child Support Calculator

For more about how we research our guides, see our editorial policy and sources methodology.

Related Guides

Learn more about related family law topics:

• Divorce in Arizona
• Child Custody in Arizona
• Child Support Calculator
• Child Custody Laws Explained
• How Much Does Divorce Cost?
• The Complete Guide to Divorce
• Get a Free Consultation

Last updated: March 2026. This guide summarizes general legal information based on publicly available sources and is provided for educational purposes only. It does not constitute legal advice. For advice specific to your situation, consult a licensed attorney in your state.