In Arizona, child support ends on the last day of the month in which the child turns 18 years old, provided the child has graduated from high school or is no longer enrolled. If the child is still attending high school or a certified GED program at age 18, support continues until the child graduates or turns 19, whichever occurs first, under ARS § 25-501(A). Arizona courts may also extend support indefinitely for a child with a severe mental or physical disability that began before age 18. The filing fee to petition for child support modification or termination in Arizona is $102 as of December 2024. Understanding exactly when child support obligations end in Arizona can save both parents thousands of dollars in unnecessary payments or enforcement actions.
| Key Fact | Detail |
|---|---|
| Standard Termination Age | 18 years old (last day of birth month) |
| High School Extension | Until graduation or age 19, whichever is first |
| Disability Exception | Indefinite if disability began before age 18 |
| Filing Fee (Modification/Termination) | $102 statewide minimum |
| Residency Requirement | 90 days domiciled in Arizona |
| Grounds for Divorce | No-fault (irretrievable breakdown) |
| Property Division | Community property (50/50) |
| Modification Threshold | 15% change from existing order |
| Support Model | Income Shares Model |
| Arrears Collection Limit | 10 years after youngest child's emancipation |
Standard Age for Child Support Termination in Arizona
Child support in Arizona terminates on the last day of the month in which the child reaches age 18, as established by ARS § 25-501(A). This termination is automatic under the law but does not automatically stop wage garnishments, which require a separate court filing. Arizona follows a strict calendar rule: if a child turns 18 on March 15, the final child support payment is due on March 31 of that year. The presumptive termination date listed in Arizona child support orders reflects this month-end calculation.
Parents should understand that child support does not simply stop the day the child turns 18. The obligation runs through the entire birth month, and the paying parent (obligor) must continue making full monthly payments until and including that final month. Stopping payments early, even by a few days, creates arrearages that accumulate interest and can trigger enforcement actions including wage garnishment, tax refund interception, and even contempt of court proceedings. Each monthly child support payment becomes enforceable as a final judgment by operation of law on the date it is due under ARS § 25-503.
High School Extension: When Child Support Continues to Age 19
Arizona extends child support beyond age 18 when the child is still attending high school or an approved GED equivalency program at the time of the 18th birthday, under ARS § 25-320(F). Support continues while the child is actually attending school but terminates no later than the last day of the month in which the child turns 19. This means when does child support end in Arizona depends on whether the child is enrolled in and actively attending a secondary education program.
The high school extension applies only to children who are genuinely enrolled in and attending a recognized high school or GED program. A child who drops out of school after turning 18 loses the extension immediately, and child support terminates at the end of that month. Parents seeking to continue support under this provision must demonstrate the child is actively enrolled. The court may require proof of enrollment, such as a school attendance record or enrollment verification letter, before extending payments past the child's 18th birthday.
The high school extension does not cover college attendance. Arizona law does not require either parent to pay child support while a child attends college or university, regardless of the child's financial dependence. Some parents include college support provisions in their divorce agreements voluntarily, but Arizona courts cannot order post-secondary education support for non-disabled adult children.
Disability Exception: Indefinite Support Past Age 18
Arizona courts may order child support to continue indefinitely past age 18 for a child with a severe mental or physical disability, under ARS § 25-320(E). Three conditions must be satisfied: the court has considered the factors outlined in ARS § 25-320(D), the child has a severe disability rendering the child unable to live independently and be self-supporting, and the disability began before the child reached the age of majority. This exception is discretionary, not automatic.
The burden of proof falls on the parent requesting continued support. Courts evaluate whether the adult child can maintain employment, manage daily living activities, and achieve financial independence. Medical documentation from treating physicians, psychologists, or psychiatrists typically forms the foundation of the evidence. Common qualifying conditions include severe autism spectrum disorder, intellectual disabilities, traumatic brain injuries sustained in childhood, and certain chronic physical conditions that prevent gainful employment.
Parents should file for post-majority disability support before the child turns 18, while the family court still has active jurisdiction. Filing after the child reaches adulthood can create jurisdictional complications. The court retains authority to modify or terminate disability-based support if the child's condition improves to the point where independent living becomes feasible.
Emancipation: Early Termination of Child Support
A minor child aged 16 or older may petition for emancipation under ARS § 12-2451, which immediately terminates the child support obligation. Arizona requires the minor to be an Arizona resident, financially self-sufficient, and not a ward of the court or in state agency custody. The filing fee for emancipation petitions may be waived for financial hardship. The court must hold a hearing within 90 days of filing, and the minor bears the burden of proof by clear and convincing evidence.
Emancipation in Arizona can also occur automatically through certain life events without a court petition. A child who marries, enters active military service, or is otherwise legally emancipated is no longer entitled to child support. The paying parent must still file a motion with the court to formally terminate the support order and stop any active wage assignments. Simply stopping payments without a court order, even after an emancipating event, can result in arrearages.
The emancipation petition must include the minor's name, address, Social Security number, and date of birth, along with proof of financial self-sufficiency. The minor must show one of three things: evidence of at least 3 months of independent living, documentation of unsafe home conditions, or notarized parental consent to the emancipation. The parent or guardian receives certified mail notice at least 60 days before the hearing and may file a written objection within 30 days.
How to File a Petition to Terminate Child Support in Arizona
The filing fee for a post-adjudication petition to modify or terminate child support in Arizona is $102 statewide, as established by Administrative Order 2024-210 effective December 28, 2024. As of March 2026, verify current fees with your local clerk. In Maricopa County, a simplified child support modification petition also costs $102. Fee waivers and deferrals are available for parents who demonstrate financial hardship.
To terminate child support in Arizona, the obligor (paying parent) must file a petition to modify or terminate with the Superior Court in the county where the original order was entered. Arizona courts do not automatically terminate support orders, even when the child reaches the statutory age. The process typically involves these steps:
- Obtain the correct forms from the Arizona Courts Self-Service Center or AZ Court Help
- Complete the Petition to Modify Child Support (form varies by county)
- File with the Superior Court Clerk and pay the $102 filing fee
- Serve the other parent with copies of the filed petition
- Attend the court hearing (if the other parent contests)
- Obtain and file the signed order terminating support
- File a motion to quash any active wage assignment with the employer
Parents who agree on termination can file a stipulation (written agreement) with the court, which costs $102 in filing fees and typically does not require a hearing. This is the fastest route when both parents acknowledge the child has reached the termination age or an emancipating event has occurred.
Wage Assignments Do Not Automatically Stop
Wage assignments (income withholding orders) in Arizona do not automatically terminate when the child reaches age 18 or 19. Under ARS § 25-504, the obligor must take affirmative action to stop the garnishment. The paying parent must either file a motion with the court to terminate the wage assignment or ensure the original support order contains a specific expiration date that the employer will honor.
This is one of the most common mistakes parents make when child support ends in Arizona. The employer continues withholding wages and remitting them to the Arizona Division of Child Support Services (DCSS) or the custodial parent until a court order directs otherwise. Overpayments can be difficult to recover. Parents anticipating termination should file the petition to terminate 30 to 60 days before the child's 18th birthday (or anticipated termination date) to ensure the court order is in place before the final month.
Arrearages: Past-Due Support Survives Termination
Child support arrearages in Arizona survive the termination of the current support obligation. Even after the child turns 18 or 19, the custodial parent retains the right to collect all unpaid child support, including interest, under ARS § 25-503. Arizona allows collection efforts for up to 10 years after the youngest child's emancipation, after which the obligor may assert unreasonable delay as a defense.
Arrearages accumulate interest at 10% per year under Arizona law. A parent who owes $10,000 in back child support at the time of termination will owe $11,000 after one year, $12,100 after two years, and so on. The custodial parent can enforce arrearages through wage garnishment, bank account levies, tax refund interception (both state and federal), property liens, passport denial (for arrearages exceeding $2,500), suspension of driver's licenses and professional licenses, and contempt of court proceedings that can result in jail time.
The only way to reduce or eliminate arrearages is through a court order. Parents cannot privately agree to forgive child support debt because the support belongs to the child, not the custodial parent. However, if both parents agree, they can petition the court to reduce arrearages to a judgment and establish a reasonable payment plan.
Modification Before Termination: The 15% Rule
Arizona allows modification of child support when there has been a substantial and continuing change of circumstances, defined as a 15% or greater variance from the existing order under ARS § 25-503(E). Either parent can petition for modification at any time this threshold is met. In Title IV-D cases (where the state provides child support enforcement services), either party can request a review every 3 years without proving changed circumstances.
Common grounds for modification before child support ends in Arizona include job loss or significant income reduction, substantial pay increases for either parent, changes in the child's medical or educational needs, changes in parenting time (the Arizona guidelines adjust support based on overnights), remarriage affecting household expenses, and addition of children from new relationships. The modification takes effect on the first day of the month following the filing of the petition, not retroactively.
The self-support reserve in Arizona's 2022 child support guidelines is $1,685 per month, representing 80% of monthly full-time earnings at the state minimum wage. Arizona courts will not set support at a level that pushes the obligor's income below this threshold, except in cases involving the minimum basic support obligation.
Arizona Child Support Guidelines: Income Shares Model
Arizona uses the Income Shares Model to calculate child support, combining both parents' adjusted gross incomes to determine the total support obligation under ARS § 25-320. The 2022 guidelines, the most recent revision, set the combined adjusted gross income cap at $30,000 per month. Federal law requires states to review guidelines every 4 years, making the next Arizona review due around 2026.
| Combined Monthly Income | 1 Child | 2 Children | 3 Children |
|---|---|---|---|
| $1,000 | $211 | $321 | $389 |
| $5,000 | $729 | $1,095 | $1,298 |
| $10,000 | $1,274 | $1,889 | $2,224 |
| $20,000 | $1,983 | $2,927 | $3,413 |
| $30,000 | $2,542 | $3,723 | $4,322 |
Arizona applies a 10% upward adjustment to the basic support obligation when one or more children in the order are age 12 or older, reflecting the higher costs of raising older children. Additional costs for health insurance premiums, childcare, and extraordinary educational or medical expenses are added to the base obligation and divided proportionally between the parents.
Parenting time directly affects the child support calculation. Arizona counts overnights using a tiered system: periods of 12 or more hours count as 1 full day, 6 to 11 hours count as 0.5 day, and 3 to 5 hours count as 0.25 day. Parents with more parenting time typically pay less in child support because they incur more direct expenses during their custodial periods.
Paternity Fraud and Termination of Support
Arizona law provides a narrow pathway to terminate child support based on paternity fraud under ARS § 25-503(F). A parent who was presumed to be the biological father may petition the court to terminate support by proving, through clear and convincing evidence, that the paternity determination resulted from fraud, duress, or a material mistake of fact. The court may order genetic testing to resolve the question.
If genetic testing disproves paternity, the child support obligation ends prospectively from the date of the court order. However, all past-due arrearages remain enforceable. Arizona does not allow retroactive elimination of support payments already owed, even when paternity is disproven. The non-biological parent has no right to reimbursement of previously paid child support.
Recent Arizona Law Changes Affecting Child Support (2024-2026)
Arizona implemented new statewide court filing fees effective December 28, 2024, under Administrative Order 2024-210. The petition for dissolution of marriage now costs $261 statewide ($176 base plus surcharges), while post-adjudication petitions for child support modification or termination cost $102. Maricopa County adds local surcharges, bringing the dissolution filing fee to $376.
Effective September 1, 2025, Arizona overhauled its spousal maintenance (alimony) guidelines, introducing a calculator tool based on Bureau of Labor Statistics data. While this change primarily affects spousal support, it indirectly impacts child support calculations because spousal maintenance received by either parent is included in gross income for child support purposes under the Arizona guidelines.
HB 2144, prefiled January 7, 2026, proposes allowing courts to order child support for "preborn children" from the date of a confirmed positive pregnancy test. The bill would cap support at actual medical and pregnancy-related expenses. As of March 2026, HB 2144 has been introduced but not enacted.
Frequently Asked Questions
At what age does child support end in Arizona?
Child support in Arizona ends on the last day of the month in which the child turns 18, under ARS § 25-501(A). If the child is still attending high school or a GED program at 18, support extends until graduation or the child's 19th birthday, whichever occurs first. The child support age limit in Arizona never exceeds 19 unless the child has a qualifying disability.
Does child support automatically stop at 18 in Arizona?
The legal obligation to pay child support ends at 18 (or 19 for high school students), but wage garnishments do not stop automatically. The paying parent must file a motion with the court to terminate the wage assignment under ARS § 25-504. Filing 30 to 60 days before the termination date prevents overpayment. The court filing fee for this motion is $102.
Can child support continue past 18 for a disabled child in Arizona?
Yes. Under ARS § 25-320(E), Arizona courts may order indefinite child support for an adult child with a severe mental or physical disability that began before age 18. The child must be unable to live independently and be self-supporting. This extension is discretionary and requires medical evidence proving the severity of the disability.
How do I terminate child support in Arizona?
File a Petition to Modify or Terminate Child Support with the Superior Court in the county of the original order. The filing fee is $102 statewide. Serve the other parent, attend any hearing, and obtain a signed court order. Then file a motion to quash any active wage assignment. Forms are available at the Arizona Courts Self-Service Center. If both parents agree, a stipulated termination avoids a contested hearing.
Does child support cover college expenses in Arizona?
No. Arizona law does not authorize courts to order child support for college or post-secondary education expenses for non-disabled adult children. The high school extension under ARS § 25-320(F) applies only to high school and GED programs, not to colleges, universities, or trade schools. Parents may voluntarily agree to share college costs in their divorce settlement, but courts cannot enforce such agreements as child support.
What happens to child support arrears after the child turns 18?
Child support arrearages survive termination of the current obligation. Under ARS § 25-503, the custodial parent can pursue collection for up to 10 years after the youngest child's emancipation. Unpaid child support accrues interest at 10% per year. Enforcement methods include wage garnishment, tax refund interception, property liens, passport denial for debts over $2,500, and contempt of court proceedings.
Can a child be emancipated to end child support early in Arizona?
Yes. A minor aged 16 or older may petition for emancipation under ARS § 12-2451. The minor must be an Arizona resident, financially self-sufficient, and prove their case by clear and convincing evidence. The court holds a hearing within 90 days. Marriage and active military service also trigger automatic emancipation. An emancipation order immediately terminates the child support obligation.
How much does it cost to modify child support in Arizona?
The statewide minimum filing fee for a child support modification or termination petition is $102, effective December 28, 2024, under Administrative Order 2024-210. Maricopa County charges the same $102 for simplified modifications. Fee waivers are available for parents demonstrating financial hardship. Attorney fees for contested modifications typically range from $1,500 to $5,000 depending on complexity.
What qualifies as a substantial change for child support modification in Arizona?
Under ARS § 25-503(E), a 15% or greater variance between the current order and the amount that would result from applying the guidelines to current circumstances constitutes a substantial and continuing change. Common triggers include job loss, significant income changes, changes in parenting time, new children, and changes in the child's medical or educational needs. In Title IV-D cases, either parent can request a review every 3 years without proving changed circumstances.
Does remarriage affect when child support ends in Arizona?
Remarriage alone does not change when child support ends in Arizona. The termination age remains 18 (or 19 for high school students) regardless of either parent's marital status. However, remarriage can affect the child support amount if it substantially changes either parent's financial circumstances. A new spouse's income is not directly included in child support calculations, but courts may consider household expenses shared with a new spouse when evaluating the obligor's ability to pay.