How Arizona Calculates Child Support
Arizona uses the Income Shares model for child support. The legal foundation is Arizona Revised Statutes Section 25-320, along with the Arizona Child Support Guidelines issued by the Supreme Court of Arizona. These guidelines were most recently updated in 2022 and apply to all child support proceedings in the state.
Arizona's approach combines both parents' gross monthly incomes to establish the total financial obligation for raising the children. Each parent then contributes their proportional share. The parent with less parenting time pays their share to the parent with more parenting time. Courts use the guidelines as the starting point in every case, and any deviation from the guideline amount requires a specific written finding from the judge.
The Arizona Child Support Formula
Arizona's calculation follows five steps.
Step one is identifying each parent's gross monthly income. Step two is calculating each parent's adjusted gross income. Arizona allows deductions for court-ordered child support or spousal maintenance being paid for other children or former spouses. If you are already paying support from a previous order, that amount is subtracted from your gross income before entering the formula. Step three is adding both adjusted gross incomes together to get the combined adjusted gross monthly income. Step four is looking up the Basic Child Support Obligation in Arizona's schedule. The schedule uses the combined income figure and the number of children to produce the total monthly obligation. Step five is calculating each parent's income share percentage and applying it to the total obligation.
A practical example: Parent A has a gross monthly income of $5,000. Parent B has a gross monthly income of $3,000. Combined adjusted income is $8,000. Parent A's income share is 62.5%. The schedule shows a basic obligation of $1,400 for two children at $8,000 combined income. Parent A's share is $875. That is the base payment before parenting time adjustments and add-ons.
What Counts as Income in Arizona
Arizona uses a comprehensive income definition. Courts count wages, salary, commissions, bonuses, overtime, tips, self-employment income, partnership and business income, rental income, pension distributions, retirement income, Social Security benefits, SSDI, unemployment compensation, workers' compensation, and income from any other source that is regularly received.
Arizona courts can impute income to a parent who is voluntarily unemployed or underemployed. The imputed amount is based on the parent's historical earnings, education, skills, and the local job market. A parent who chooses to work part time when full-time work is available at their skill level can expect the court to calculate support based on full-time equivalent earnings.
One notable Arizona rule: income from a new spouse or partner is not counted as income for child support purposes. However, a new spouse's income may indirectly reduce a parent's living expenses, which can be considered in deviation cases.
Step-by-Step: How to Use This Calculator
Step 1 — Get your gross monthly income. Use your income before taxes and before any payroll deductions. If you receive irregular income like bonuses or commissions, average your last 12 months of total earnings and divide by 12.
Step 2 — Subtract existing child support or spousal maintenance payments. If you are already paying court-ordered child support or spousal maintenance for someone other than this case, subtract that amount from your gross income. This is your adjusted gross income.
Step 3 — Estimate the other parent's adjusted gross income. Apply the same logic to Parent B's income.
Step 4 — Enter the number of children covered by this order.
Step 5 — Enter parenting time. Count the actual overnights each parent has per year. Divide your overnights by 365 to get your percentage.
Step 6 — Add healthcare costs. Enter the monthly premium paid for the children's health insurance. Only include the children's portion of the premium, not the employee-only rate.
Step 7 — Add childcare costs. Enter monthly work-related childcare expenses.
Step 8 — Review the breakdown. Confirm the income share percentages look right before accepting the result.
Parenting Time Adjustments in Arizona
Arizona applies a parenting time credit that reduces the paying parent's obligation as their time with the children increases. The credit is more aggressive than in some states.
At the standard every-other-weekend schedule (approximately 20 percent of overnights), the credit is minimal. As parenting time approaches 45 to 50 percent, the Arizona formula applies a substantial credit because both parents are directly spending on the children during their time. At equal parenting time with equal incomes, the obligations offset each other and the net payment approaches zero.
Arizona uses a specific parenting time adjustment table within its guidelines. The calculator applies the correct credit based on the overnight percentage you enter. If you are in a near-equal parenting arrangement, even a few extra overnights per month can meaningfully change your obligation.
Add-On Expenses in Arizona
Arizona adds healthcare premiums and work-related childcare to the base obligation. Both add-ons are split proportionally by income. Courts may also address extraordinary medical costs, educational expenses, and other specific costs on a case-by-case basis.
When one parent pays for health insurance, they receive a credit for the children's portion of that premium within the formula. This credit reduces the net amount they pay to the other parent.
Reading Your Results
The results display shows the combined adjusted income, the Basic Child Support Obligation, each parent's income share, the parenting time adjustment applied, add-on allocations, and the final monthly obligation. The bottom line is the net monthly transfer from the paying parent to the receiving parent.
Arizona's results include an annual projection and a projection through the child's 18th birthday. Use those numbers to understand the long-term financial picture, especially if you are considering a custody modification.
After You Get Your Estimate
Arizona courts follow the guidelines in most cases. A judge can deviate when the guideline amount is unjust or inappropriate, but must state the reasons in writing. Common deviation grounds include special needs of the child, unusually low or high income, significant debt obligations, or a parent's substantial non-monetary contributions.
Arizona allows modification when there has been a substantial and continuing change in circumstances. A 15 percent or more change in the calculated obligation is typically the threshold. If your income has changed significantly, if parenting time has shifted, or if the children's needs have changed substantially, a modification filing may be appropriate.
Connect with a licensed Arizona family law attorney to review your specific situation — many provide a free consultation for new child support cases.