How Arizona calculates child support
Arizona uses an income shares model. The Arizona Supreme Court sets the Arizona Child Support Guidelines under A.R.S. ยง 25-320, and the version in force took effect on January 1, 2022, with revisions dated September 21, 2022. The guideline amount is presumed correct. A revised guideline is under review and may apply to orders entered from 2027; the calculator follows the version currently in force.
Each parent's Child Support Income
Child Support Income is income from any source before taxes or withholdings: wages, bonuses, commissions, self-employment profit after ordinary business expenses and half of the self-employment tax, pensions, interest, unemployment and disability benefits, and spousal maintenance received (Guidelines Section II.A). Child support received and means-tested assistance such as TANF and SSI are left out. Taxes are not deducted because the schedule already accounts for them.
Adjustments to income
Court-ordered spousal maintenance paid for this marriage and court-ordered support paid for children of another relationship are subtracted (Section II.B). A parent who is the primary residential parent of other children may reduce income by up to the schedule amount for those children on that parent's own income. When a parent has essentially equal parenting time with a child of another relationship, the adjustment for that child can be made either way, by the support paid or by the schedule amount, whichever gives the higher deduction, but not both (Section II.B.2.e). If the adjustment for other children and the self-support reserve together would leave almost nothing for the children in the case, the adjustment should be reduced so that all of the parent's children are treated equally (Section II.B.2.f). That is a new calculation with a higher income for the paying parent, so its result can be above the first guideline amount; the calculator shows it as a separate figure, with its own reserve test, and does not present it as a reduction.
The basic obligation
The parents' adjusted incomes are added and the Schedule of Basic Support Obligations gives the amount for one to six children. The schedule runs from $750 to $30,000 of combined monthly income in steps of $50; the row closest to the combined income is used, and an income exactly halfway rounds up (Section III.A). Above $30,000 the $30,000 amount applies unless a parent asks the court for more. For more than six children the six-child amount is presumed.
Older children and added costs
The basic obligation increases by 10% when all children qualify, from the day after the 12th birthday; otherwise, the increase is prorated: the basic obligation is divided by the number of children and 10% of the portion for each child over 12 is added (Section III.B.2). The children's share of medical, dental and vision insurance premiums (for a plan that also covers other people, the cost of the dependent coverage divided by the dependents covered, or else the total cost divided by everyone covered, times the children in the case), child care paid so a parent can work or look for work, and agreed or ordered private school or special needs costs are then added. Costs that vary during the year are averaged over 12 months.
Income shares and parenting time
Each parent's share of the total follows that parent's share of combined income (Section IV). The calculator uses each parent's exact share of income, so a worksheet that rounds the percentage may differ by a few dollars. The parent with less parenting time then subtracts a percentage of the basic obligation plus any older child adjustment, taken from the Parenting Time Table for that parent's days per year (Section V.D). A day is each 24 hours, with leftover blocks of 12 hours or more counting as a full day, 6 to 11 hours as half a day and 3 to 5 hours as a quarter; shorter periods may count as a quarter day when the parent with less time pays routine expenses such as meals (Section V.C). The calculator accepts quarter days. The table's rows are whole numbers, so a total such as 19.5 falls between two rows, and the Guidelines do not say which one applies: the calculator uses the nearest whole day and shows the result with the other row too.
| Parenting-time days per year | Adjustment |
|---|---|
| 0 to 19 | 0% |
| 20 to 34 | 2.5% |
| 35 to 49 | 5% |
| 50 to 69 | 7.5% |
| 70 to 84 | 10% |
| 85 to 99 | 15% |
| 100 to 114 | 17.5% |
| 115 to 129 | 20% |
| 130 to 142 | 25% |
| 143 to 152 | 32.5% |
| 153 to 163 | 40% |
| 164 or more | 50% |
When each parent has more than half the time with at least one child, two worksheets are prepared and the amounts are netted (Section V.F). When the children have different schedules but one parent does not have more than half the time with any of them, one worksheet is used with that parent's average days per child: for example, no time with one child and essentially equal time (182 days) with the other averages 91 days.
Credits and who pays
A parent who pays the insurance, child care or school costs directly subtracts them from that parent's share (Section VI). A positive result is paid by the parent with less time; with essentially equal time, by the parent with the higher income. A negative result reverses the direction. The final award is rounded to the nearest dollar. If the amount is less than the current Support Clearinghouse fee, the court does not impose an award unless a deviation is warranted (Section X.A.5). The Guidelines do not state the fee, so the calculator does not apply this rule.
Social Security retirement or disability benefits that a child receives because of the paying parent's work record are credited against that parent's obligation. If the benefit equals or exceeds the obligation, the obligation is satisfied for that month, and any excess is not a credit for arrears or future months; if it is less, the paying parent pays the difference unless the court sets the order equal to the benefits (Section X.B.1). Supplemental Security Income, adoption subsidies and benefits arising from a child's own disability are not credited (Section X.B.3).
Medical, dental and vision costs that insurance does not cover are not part of the monthly amount; the order sets the percentage each parent pays. Unless good cause is shown, a request for reimbursement must reach the other parent within 180 days of the expense, with the date of service, the provider and a short description, and that parent pays or agrees a payment plan within 45 days of receiving it unless the court orders otherwise (Section X.C).
The self-support reserve test
The reserve is 80% of full-time monthly earnings at the state minimum wage for the year of the calculation (Section VIII). Based on a 2026 minimum wage of $15.15 an hour, the calculator uses $2,101 a month. If the paying parent's adjusted income minus the reserve is less than the guideline amount, the court may lower the order to that difference, or to zero or a nominal amount when nothing is left, after applying the same test to the receiving parent and considering the effect on that household. The reduction is not automatic, so the calculator shows both figures with equal weight: the guideline amount and the amount after the reserve test.
When a court can order a different amount
A court may deviate when applying the Guidelines would be inappropriate or unjust, after considering the child's best interests and stating in writing what the order would have been (Section IX). Listed situations include a large income gap with significant time for both parents, combined income above $30,000, one parent paying a disproportionate share of the children's expenses, and significant travel costs for parenting time.