Shared Custody Child Support in Alaska
When the children live with each parent at least 30% and no more than 70% of the year, Alaska figures what each parent would pay under the primary-custody formula, multiplies each figure by the other parent’s time share, and has the parent with the larger result pay the difference multiplied by 1.5, capped at the primary-custody amount.
What counts as shared custody
Under Rule 90.3(f)(1), a parent has shared physical custody if the children live with that parent for a period specified in writing in the custody order of at least 30, but no more than 70, percent of the year, regardless of the status of legal custody. The court form puts 30% at roughly 110 overnights a year. If the children live with the other parent less than 30% of the year, that parent has primary custody and the ordinary percentage formula applies (Rule 90.3(f)(2)).
The formula, step by step
- Figure the annual support each parent would pay if the other parent had primary custody, using the usual percentage of adjusted annual income. The $138,000 cap and the $600 a year minimum apply to each figure.
- Multiply each parent’s figure by the percentage of time the other parent has the children.
- The parent with the larger result is the paying parent. The annual award is the difference between the two results multiplied by 1.5.
- If that amount is higher than the paying parent would owe under the primary-custody formula, the primary-custody amount is the award instead (Rule 90.3(b)(1)).
- Divide by 12 for the monthly payment (Form DR-306, line 10).
A worked example
You earn $72,000 and the other parent earns $30,000, with the same deductions as in how Civil Rule 90.3 calculates child support and two children (27%). The children live with you 60% of the year.
| Item | Amount |
|---|---|
| Your adjusted annual income | $48,600.00 |
| Other parent's adjusted annual income (low-income adjustment) | $22,500.00 |
| Annual support if each had primary custody, you / other | $13,122.00 / $6,075.00 |
| Time with you / with the other parent | 60% / 40% |
| Each figure x the other parent’s time share, you / other | $5,248.80 / $3,645.00 |
| Difference x 1.5 | $2,405.70 |
| Smaller of that and your primary-custody figure | $2,405.70 |
| Monthly support paid by you | $200.48 |
The Alaska child support calculator runs the same formula when you set the share of the year with you to 60%.
Payment schedule and the duty to use the time
The award is paid in 12 equal monthly installments, except that when shared custody is based on the paying parent having the children for periods of 30 consecutive days or more, the annual award may be paid over the months in which the paying parent does not have the children, and a seasonal income can lead to unequal payments. The order must state that failing to exercise enough physical custody to qualify for shared custody is grounds for modification, and denial of visitation by the custodial parent is not cause to increase child support (Rule 90.3(b)(1)(D)–(E)).
Varying the percentage and other custody types
If the court finds that the time percentages will not accurately reflect the funds each parent directly spends on the children, it must vary the percentage to reflect its findings (Rule 90.3(b)(1)(B)). Divided custody (each parent has primary custody of at least one child) and hybrid custody (at least one child in primary custody of a parent and at least one in shared custody) have their own calculations in Rule 90.3(b)(2) and (b)(3), with separate court forms, and are not covered by the calculator.
Frequently asked questions
When does Alaska use the shared custody formula?
When the custody order specifies that the children live with each parent at least 30% and no more than 70% of the year.
How is Alaska shared custody child support calculated?
Each parent's primary-custody amount is multiplied by the other parent's share of the time; the parent with the larger figure pays the difference multiplied by 1.5, but not more than the primary-custody amount.
How many overnights is 30% in Alaska?
The court's Form DR-306 describes 30% as roughly 110 overnights during the year.
Does 50/50 custody mean no child support in Alaska?
No. The formula is an offset, and the parent with the larger figure still pays the difference multiplied by 1.5.
What if a parent does not use the shared custody time?
The order must say that failing to exercise sufficient physical custody to qualify for shared custody is grounds for modification of child support.
Official sources
A local family law attorney can review your situation — many offer a free consultation.
This is general information, not legal advice. It is based on the cited Alaska statutes, rules and court opinions, and every case turns on its own facts. Confirm how the law applies to your situation with a licensed Alaska attorney.