Idaho child support guidelines
Idaho uses an income-shares guideline — the Idaho Child Support Guidelines (IRFLP 120) — built on both parents’ incomes and parenting time. This page explains it and links the official court worksheets; it doesn’t compute your amount.
How the Idaho formula works
The guidelines work in steps:
- Combine both parents’ gross incomes;
- Find the basic obligation for that combined income and the number of children;
- Allocate it proportionally by each parent’s income share;
- Adjust for parenting time, and add health insurance and childcare.
Idaho publishes two worksheets — the Standard worksheet (CAO FL 1-13, when one parent has 75%+ of the time) and the Shared/Split/Mixed worksheet (CAO FL 1-12, when both have more than 25%).
Shared custody, the subsistence review, and duration
Idaho’s biggest swing factor is the 25% parenting-time line (about 91 overnights each). Cross it and the shared-custody worksheet applies: the basic obligation is multiplied by 1.5 to reflect two active households, each parent’s share is figured, and the results are offset so the higher obligor pays the difference. Idaho is also distinctive in not building in a standard self-support reserve — but when a paying parent earns under about $800/month, the court reviews the order to protect basic subsistence. Support generally runs to 18, or 19 while still in high school, an order can be modified on a substantial and material change, and a court can impute income to a voluntarily unemployed or underemployed parent.
Use the official worksheets
The Idaho Supreme Court publishes the Child Support Guidelines and worksheets (linked above); the Court Assistance Office can help you complete them. Use them for an estimate; this page only explains the model. The court has final authority over the amount.
For a real case
The guideline amount is presumed correct but can be adjusted when it would be unjust. For advice on your situation, consult an Idaho family-law attorney.
Reviewed by Aqil Abbas Khan, Founder & Editor of ToolsNexus
This page is general information, not legal advice. Child support in Idaho is set by Idaho’s official guidelines, and the amount in any real case is determined by the court or the state child-support agency using the official worksheet — not by this page. Guideline figures, schedules, and adjustments change over time and depend on facts specific to your situation (each parent’s income, parenting time, health-insurance and childcare costs, and other factors a court may consider). Use the official Idaho calculator for an actual estimate, and consult a licensed family-law attorney in Idaho for advice about your circumstances. ToolsNexus is not a law firm and does not provide legal representation.
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Frequently asked questions
- How is child support calculated in Idaho?
- Idaho uses an income-shares model in the Idaho Child Support Guidelines (IRFLP 120). It combines both parents' gross incomes, finds the basic support obligation for that combined income and the number of children, and allocates it by income share — adjusted for how much parenting time each parent has.
- Which worksheet applies to my case?
- Use the Standard Child Support Worksheet (CAO FL 1-13) when one parent will have at least 75% of parenting time. Use the Shared, Split, or Mixed Custody Worksheet (CAO FL 1-12) when both parents have more than 25% of the time (roughly 91+ overnights each).
- How does shared custody change the amount?
- When both parents have more than 25% of the parenting time, Idaho applies a shared-custody adjustment: the basic obligation is multiplied by 1.5 to reflect the cost of two active households, each parent’s share is figured, and the amounts are offset so the higher obligor pays the difference. That 1.5 multiplier can change the number a lot.
- Is there a self-support reserve, and until what age is support paid?
- Unlike most states, Idaho’s guidelines do not build in a standard self-support reserve — but when a paying parent’s income is under about $800 a month, the court reviews the order to leave enough for basic subsistence. Support generally runs until the child turns 18, or up to 19 while still in high school.
- Where do I get an official estimate?
- Use the Idaho Child Support Guidelines and worksheets linked on this page. The Court Assistance Office can help you fill out the worksheet. This page explains the model but does not compute an amount, and it is not legal advice.