How Alaska Calculates Child Support

Alaska uses the Percentage of Obligor's Adjusted Annual Income model to determine child support obligations. This page explains the guidelines, formula, and key factors.

Model Type

Percentage of Obligor's Adjusted Annual Income (Alaska Civil Rule 90.3)

Alaska applies a flat percentage to the paying parent's adjusted annual income, set by the number of children -- 20% for one child up to 42% for six. Shared custody, where both parents have between 30% and 70% of the year, cross-calculates each parent's theoretical obligation and applies a 1.5× multiplier to the difference.

Sources & Verification

Core formula verified; some gaps disclosed below

Guideline effective 2018-09-13 · last checked against the primary source 2026-08-26

Primary sources

Alaska Civil Rule 90.3 — Child Support Awards (current as of 2023-10-16)Form DR-310 — How to Calculate Child Support Under Civil Rule 90.3

What this calculator doesn't yet handle

Shared custody rounds each parent's custody-time percentage (form DR-306, Lines 3-4) to the nearest whole point before multiplying, matching the official filled-out DR-306 example (30%/70% from a 110/255-overnight split, not the exact 30.137%/69.863%) exactly. This is inferred from the example's precision rather than stated as an explicit rounding rule in Rule 90.3's text, the same kind of judgment call this codebase already documents for Pennsylvania's obligor income share.
Pending verification: a 2025 Child Support Guidelines Review Committee has proposed raising Rule 90.3(c)(2)'s income cap from $138,000 to $155,000 and eliminating the $50/month minimum order under 90.3(c)(3), with public comments due 2026-10-02. Neither change is adopted as of this calculator's last verification date; this calculator implements the current, in-force figures ($138,000 cap, $50 minimum).
Net income is estimated from gross using 2026 federal tax brackets and FICA (shared/ak-tax.ts) rather than requiring the sworn, documented figures Rule 90.3(e)(1) contemplates (form DR-305, with attached tax returns and pay stubs). Alaska has no state income tax, so no state-tax estimate is needed. An exact adjusted annual income can be entered directly, bypassing the estimator.
The net-income estimator models only the single-filer status and the standard deduction; head-of-household and married-filing-jointly are not modeled, nor are the federal Child Tax Credit or Earned Income Tax Credit.
Divided custody (90.3(b)(2)) and hybrid custody (90.3(b)(3)) are not implemented — the calculator collects a single overnight split for all children, which cannot express either arrangement. Both additionally require a mandatory judicial variance analysis under 90.3(c)(1) that this calculator does not perform.
The extended visitation credit (90.3(a)(3), up to a 75% reduction for visitation periods over 27 consecutive days) is not calculated, only disclosed — it is explicitly discretionary and order-specific.
Potential/imputed income for a voluntarily and unreasonably unemployed or underemployed parent (90.3(a)(4)) is not calculated — the rule sets out three threshold factors and eight amount factors, all fact-intensive.
The (a)(1)(D) deduction for in-kind support of prior children in the parent's own custody is not implemented — it requires running a nested Rule 90.3 calculation for those children.
The (c)(1) "manifest injustice" variance, grandparent support orders (90.3(c)(4)), seasonal-income unequal payments (90.3(c)(5)), and third-party custody (90.3(i)) are not calculated, only disclosed.