Child Support Calculations in Alaska

Alaska uses a percentage-of-income model under Civil Rule 90.3, with different formulas for primary, shared, divided, and hybrid custody arrangements. Whether you're navigating an uncontested or contested divorce, understanding the percentages, custody thresholds, and the 1.5x shared-custody multiplier is essential.

The Percentage-of-Income Model

Alaska calculates child support based on the non-custodial parent's Adjusted Annual Income (AAI). The core percentages for primary custody are:

• One child: 20% of AAI
• Two children: 27% of AAI
• Three children: 33% of AAI
• Each additional child: +3%

• High-income cap: $138,000 AAI (excess excluded unless "just and proper")
• Minimum order: $50/month
• Low-income adjustment: If total income ≤$30,000, AAI = lesser of normal calculation or (gross − $7,500)

Don't guess your obligation. Enter your income and custody split for Alaska's Rule 90.3 guidelines:

Custody Types and Formulas

Primary Physical Custody (70%+ Overnights)

One parent has the child 70% or more of the time. The non-custodial parent pays their percentage of AAI.

Shared Physical Custody (30-70% Each)

Each parent has 30-70% of overnights (~110-255 nights yearly). The shared formula under Rule 90.3(b)(1):

1. Compute each parent's primary amount as if the other had primary custody
2. Multiply each by the other parent's custody percentage
3. Subtract smaller from larger
4. Multiply difference by 1.5
5. Cap: result cannot exceed primary-schedule amount

Divided Custody

Each parent has primary custody of at least one child (no shared child):

• Compute each parent's primary obligation for children in other's custody
• Offset the two amounts

Hybrid Custody

At least one child in primary arrangement and at least one in shared custody. Apply primary formula for primary children and shared formula for shared children, then combine with pro-rata adjustments.

What Counts as Income

Under Rule 90.3, total income includes:

• Wages: Including overtime and tips
• Benefits: Social Security, unemployment, workers' comp, pensions
• Business income: Net of ordinary/necessary expenses
• Investment income: Dividends, interest, rental income
• Alaska Permanent Fund Dividend (PFD): Included as income
• In-kind benefits: Housing, vehicle use that reduces living expenses

Allowable Deductions (to reach AAI)

• Federal, state, and local income taxes
• Social Security/Medicare/self-employment tax
• Union dues and mandatory retirement contributions
• Voluntary retirement up to 7.5% of total income (combined with mandatory)
• Prior court-ordered support actually paid
• Work-related childcare for subject children
• Parent-only health insurance (up to 10% of income)
• Life insurance premiums ($1,200/year cap)

Need a Deeper Analysis?

The calculator above gives you a quick Rule 90.3 estimate. For a comprehensive report covering shared custody multipliers, deviation factors, and PFD income adjustments, get your full Alaska analysis here. For official calculations, use the CSSD Guideline Calculator.

Medical Support

Under Rule 90.3(d):

• Insurance requirement: Must be ordered if available at "reasonable cost"
• Reasonable cost: Presumed if ≤5% of that parent's AAI
• Cost allocation: Children's portion split equally by default
• Uninsured expenses: Split equally unless >$5,000/year (then by relative means)

Extended Visitation Credit

In primary custody cases, the court may allow the obligor to reduce support by up to 75% for extended visitation exceeding 27 consecutive days. The order must specify the reduction amount and conditions.

When Courts May Deviate

Deviation requires "clear and convincing evidence" that the presumptive result would cause "manifest injustice." Factors include:

• High income: AAI above $138,000 may justify higher awards
• Extraordinary needs: Medical, educational, or special needs
• Long-distance visitation: Travel costs
• Seasonal income: Uneven monthly payments may be ordered
• Time vs. spending: If time percentages don't reflect actual spending ratios

Duration of Support

• Standard termination: Age 18
• High school extension: Unmarried 18-year-old in high school, living as dependent (until graduation or age 19)
• Disabled adult children: Alaska courts may order support for adult child incapable of self-support due to disability

Modification Rules

Under Rule 90.3(h):

• 15% threshold: Presumed material change if recalculated support differs by >15%
• 3-year reviews: Allowed without showing material change
• No retroactivity: Modifications effective from service of motion
• Annual income exchange: Either parent may request other's tax return once per year

Enforcement Tools

Alaska CSSD employs:

• Income withholding: Immediate and mandatory in all orders
• PFD intercept: Alaska Permanent Fund Dividends can be levied
• Tax refund intercepts: Federal and state
• Liens: Filed when arrears exceed $2,500 or 12× monthly obligation
• Credit reporting: When arrears exceed $1,000
• License suspension: Driver's and occupational licenses
• Passport denial: At $2,500+ arrears

Interest on Arrears

Under AS 25.27.025:

• Interest rate: 6% per year
• Compounding: None (simple interest)
• Application: Payments apply to principal first, then interest

Key Takeaways

• Percentage-of-income model: 20%/27%/33%/+3% for 1/2/3/additional children
• $138,000 AAI cap: Excess excluded unless "just and proper"
• $50 minimum order
• 30% shared threshold: Each parent must have 30-70% of overnights
• 1.5x multiplier: In shared custody calculations
• 75% extended visitation credit: For >27 consecutive days
• 5% medical cap: For "reasonable cost" health insurance
• 15% modification threshold
• 6% simple interest: On arrears

For more information about Alaska divorce processes, see our Alaska divorce timeline and filing checklist. For property division information, review our Alaska marital property guide.