Estimate monthly child support using Arizona's Income Shares Model — with a transparent, step-by-step breakdown most calculators hide.
Educational estimate — not legal advice. The court sets the binding amount and may deviate for good cause. Source: 2022 Arizona Child Support Guidelines.
Arizona uses the Income Shares Model under A.R.S. § 25-320 and the Arizona Child Support Guidelines adopted by the Arizona Supreme Court (current version effective January 1, 2022). The idea is simple: estimate what the parents would have spent on the children if the household had stayed intact, then divide that responsibility in proportion to each parent's income.
This is where Arizona differs most from other states. There is no reduction below 95 overnights per year. Above that, the paying parent's obligation drops on a sliding scale:
| Annual Parenting Days (overnights) | Approx. Reduction |
|---|---|
| 0 – 94 | 0% |
| 95 – 99 | ~14% |
| 100 – 114 | ~17% |
| 115 – 127 | ~20% |
| 128 – 142 | ~26% |
| 143 – 152 | ~31% |
| 153 – 162 | ~36% |
| 163 – 172 | ~40% |
| 173 – 182 | ~46% |
| ~182 (equal time) | ~50% |
Percentages are representative of the Guidelines bands; the official worksheet uses an exact figure for the precise number of days.
Arizona casts a wide net: salary, wages, overtime, commissions, bonuses, self-employment profit, rental income, pensions, annuities, severance, and Social Security retirement/disability (not SSI). Means-tested benefits — TANF, SNAP, SSI — are excluded. A parent who is unemployed or underemployed by choice may be assigned attributed income, often at minimum wage or higher based on work history.
Arizona protects low-income paying parents with a self-support reserve — roughly $1,800/month for 2026 (tied to 80% of full-time minimum wage). If a full order would push the paying parent below that reserve, the court can reduce the support amount so the parent can still meet basic living costs.
Support normally ends when the child turns 18, or on graduation/age 19 if the child is still in high school. Arizona courts cannot order college support unless both parents agree in writing. Support may continue indefinitely for a child with a severe, demonstrable disability that began before adulthood.
Either parent can ask the court to modify support after a substantial and continuing change of circumstances. A change that alters the calculated amount by 15% or more generally qualifies for Arizona's simplified modification process; smaller changes use the standard petition.