How Alaska Calculates Child Support
Alaska uses a percentage of income model for child support: in primary custody cases, support is a percentage of the paying parent's adjusted income, and Alaska bases that figure on net income rather than gross income. The governing authority is Alaska Civil Rule 90.3, which courts have applied since 1987. Understanding the net income basis is the single most important thing to get right before using this calculator.
Net income means your income after mandatory deductions — specifically after federal and state taxes, Social Security, and Medicare. This is closer to what you actually take home each month. Most states use gross income as the starting point. Alaska's use of net income generally results in lower raw dollar figures going into the formula, so the percentages apply to a smaller base.
The Alaska Child Support Formula
Alaska applies different formulas depending on the custody arrangement.
For primary physical custody situations, where the children live primarily with one parent, Alaska calculates support as a percentage of the paying parent's adjusted net income. For one child, the percentage is 20 percent of the paying parent's monthly net income. For two children, it is 27 percent. For three children, it is 33 percent. Each additional child adds 3 percent, so four children is 36 percent and five children is 39 percent.
For shared physical custody, where each parent has at least 30 percent of the overnight parenting time, Alaska applies a combined income formula. Both parents' net incomes are used, and each parent's obligation is calculated based on their proportional income share and their parenting time percentage. The two calculated obligations are then offset against each other. The parent with the higher net obligation pays the difference.
At 50/50 parenting time, the offset often results in a relatively small payment or no payment at all if the parents' incomes are close to equal. When one parent earns significantly more, a meaningful payment remains even at equal parenting time.
What Counts as Income in Alaska
Alaska's definition of income is broad and includes wages, salaries, overtime, self-employment income, business profits, rental income, pension and retirement distributions, Social Security benefits, SSDI payments, unemployment compensation, and workers' compensation. Courts also include regular monetary gifts and income from any source a party regularly receives.
Alaska courts can impute income to a parent who is voluntarily underemployed or unemployed. The court looks at the parent's work history, education, and the local job market to assign a reasonable income figure. Parents cannot reduce their child support obligation by choosing not to work.
Alaska also considers the cost of living when determining whether a deviation from the guideline is appropriate. The state's cost of living varies significantly between Anchorage, Fairbanks, and rural communities. Courts can account for this in appropriate cases.
Step-by-Step: How to Use This Calculator
Alaska's net income basis means your first step is slightly different from most states.
Step 1 — Calculate your net monthly income. Start with your gross monthly income. Subtract federal income tax (use your actual withholding or estimate using your effective tax rate). Subtract the Alaska state income tax — Alaska has no state income tax, so this is zero. Subtract Social Security (6.2% of gross up to $176,100 annually in 2026) and Medicare (1.45% of all gross income). The result is your approximate net monthly income.
Step 2 — Estimate the other parent's net monthly income. Apply the same calculation to their gross income. Use your best estimate if you do not know their exact income.
Step 3 — Determine your custody arrangement. Are the children primarily with one parent, or do both parents have at least 30 percent of overnights? Your answer determines which formula the calculator applies.
Step 4 — Enter parenting time. Count your actual overnight stays per year and divide by 365. If you have the children roughly one-third of the time, you are near the 33 percent mark.
Step 5 — Add healthcare and childcare costs. Enter the monthly cost of health insurance for the children and any work-related childcare expenses.
Step 6 — Review and interpret your results.
Parenting Time Adjustments in Alaska
For primary custody situations, Alaska Civil Rule 90.3 does allow adjustments when the non-custodial parent has significant parenting time. The key threshold is 30 percent of overnights per year — approximately 110 nights. When parenting time reaches or exceeds that threshold, the shared custody formula typically applies.
Below 30 percent, the primary custody percentage formula is used with no parenting time credit. This makes Alaska more straightforward than many states for standard custody arrangements: if the children live primarily with one parent, the paying parent simply pays the applicable percentage of their net income.
Add-On Expenses in Alaska
Alaska adds childcare costs and health insurance premiums to the base support obligation. These are allocated proportionally based on each parent's share of the combined net income. Courts may also address extraordinary medical expenses and, in some cases, education costs.
Alaska courts have discretion to deviate from the guideline when the result would be manifestly unjust. Large income disparities, special needs of the children, and significant cost-of-living differences between parents' locations are factors courts consider.
Reading Your Results
Your results will show the net monthly income for both parents, the applicable formula used, the base obligation, the parenting time adjustment if any, add-on costs, and the final monthly transfer amount.
Remember that the number shown is based on net income inputs. If you entered gross income instead of net, your result will be higher than what an Alaska court would actually order. Double-check your income entry method before drawing conclusions.
After You Get Your Estimate
Alaska allows modification of child support orders when there has been a material change in circumstances. A change of 15 percent or more in the calculated amount is generally considered material. Common triggers include a significant income change for either parent, a change in the custody arrangement, or a change in the children's needs.
If your parenting time has changed and is now at or above 30 percent, you may be entitled to a recalculation using the shared custody formula. That change alone can result in a meaningful reduction in the monthly obligation.
Talk to a licensed Alaska family law attorney to review your calculation and advise on your options — most offer a free initial consultation.