Idaho Child Support Calculator (2026)
Idaho calculates child support under income-shares guidelines (Idaho R. Fam. L. P. 120 (Idaho Child Support Guidelines), adopted pursuant to Idaho Code § 32-706(5)). Estimate the guideline amount below.
Income basis: combined annual gross Guidelines Income of both parents.
Enter the income above to see the guideline estimate.
Simplified guideline estimate, interpolated from the official schedule — before health-insurance, childcare, and parenting-time adjustments. For the exact figure use the official Idaho calculator.
Your Case Details
Answer a few questions to see your estimated range.
Approximate gap between higher-earner and lower-earner.
Estimated Monthly Support
$840 — $1,560
State formulas vary significantly. This estimate uses national averages — your state's guidelines may produce a different number.
Editorially Reviewed — Content reviewed for accuracy using published legal research, government data, and verified court records. See our methodology
Reviewed by Leonard Goldberg, Editor · Last updated
Idaho uses the income-shares model: both parents' incomes are combined, the official schedule sets a basic support obligation, and each parent owes their proportional share (Idaho R. Fam. L. P. 120 (Idaho Child Support Guidelines), adopted pursuant to Idaho Code § 32-706(5)). The calculator above interpolates the official schedule for a quick estimate — health-insurance, child-care, and parenting-time adjustments come on top.
How Idaho Calculates Child Support
Idaho uses an Income Shares model under Idaho Rules of Family Law Procedure (I.R.F.L.P.) Rule 120 — the 'Idaho Child Support Guidelines' (I.C.S.G.), amended effective July 1, 2022. Unlike most income-shares states, Idaho applies the formula to the parents' COMBINED GROSS annual income (before taxes), not net income. Instead of a printed income-bracket lookup table, Rule 120(i) uses a declining marginal-rate formula (18% down to 5% of combined income, depending on the number of children) to produce the Basic Child Support obligation, which is then divided between the parents in proportion to each parent's share of combined Guidelines Income. The formula runs up to $440,000 of combined annual Guidelines Income; above that, courts apply enumerated factors instead of a further percentage.
Statutory basis: Idaho R. Fam. L. P. 120 (Idaho Child Support Guidelines), adopted pursuant to Idaho Code § 32-706(5). Exact figure: official Idaho calculator.
Official Schedule — Excerpt
Basic support obligation at selected combined incomes (combined annual gross Guidelines Income of both parents), from the official Idaho schedule:
| Combined income | 1 child | 2 children | 3 children |
|---|---|---|---|
| $40,000 | $6,400 | $9,600 | $11,200 |
| $60,000 | $8,900 | $13,300 | $15,600 |
| $90,000 | $11,900 | $17,600 | $20,800 |
| $120,000 | $13,600 | $20,200 | $24,300 |
Worked Example
Official Rule 120 example (I.R.F.L.P. 120(i)(3)): Two parents have two children. Parent A earns $25,000/year, Parent B earns $10,000/year — combined Guidelines Income of $35,000. Applying the two-children bracket rates (26% of the first $10,000 = $217/mo, 25% of the next $10,000 = $208/mo, 23% of the next $10,000 = $192/mo, 22% of the remaining $5,000 = $92/mo), the total Basic Child Support obligation is $709/month. That amount is divided between the parents in proportion to their share of combined income. Because Parent A has 25% or less of the overnight parenting time, Parent A pays 71% of the total — $506/month — to Parent B, the custodial parent.
When Courts Deviate From the Guideline
- The financial resources of the child
- The financial resources, needs, and obligations of both parents
- The standard of living the child enjoyed during the marriage
- The physical and emotional condition and needs of the child, including educational needs
- Any special impairment, limitation, or disability of the child and any need for special education
- Any special ability or talent of the child and the cost of educating or training that ability
- Any special living conditions that create additional costs for the child
Frequently Asked Questions
Is there a cap on the income used to calculate Idaho child support?
The Idaho Child Support Guidelines' bracket formula runs to $440,000 of combined annual gross income (I.R.F.L.P. 120(i)(7)). Support on the first $440,000 is always calculated under the standard formula. For any additional combined income above $440,000, Idaho courts do not apply a further percentage — instead they weigh factors such as the child's financial resources, the marital standard of living, and the child's educational, medical, or special needs to decide whether extra support is warranted.
What counts as income under Idaho's child support guidelines?
Idaho defines 'Guidelines Income' very broadly as GROSS income 'from any source' — before taxes — including wages, salaries, commissions, bonuses, self-employment/business/rental income, dividends, pensions, Social Security, workers' compensation, unemployment and disability benefits, alimony/maintenance received, veterans' benefits, and even certain disability or retirement dependency benefits paid on a child's behalf (I.R.F.L.P. 120(e)). Public-assistance benefits generally count too, except in cases of extraordinary hardship. Idaho is unusual among income-shares states in using GROSS rather than net income as its base.
How does shared or split custody affect the Idaho calculation?
If a child spends MORE than 25% of overnights in a year with each parent, Idaho applies a 'Shared Physical Custody' adjustment (I.R.F.L.P. 120(i)(4)): the Basic Child Support obligation is multiplied by 1.5, apportioned by each parent's income share, then multiplied again by the percentage of time the child spends with the OTHER parent; the two resulting obligations are offset, and the parent owing more pays the difference. At 25% of overnights or less, the standard (unmultiplied) obligation applies unchanged.
Until what age does child support run in Idaho, and does it cover college?
Support is owed for children under 18, or up to age 19 if the child is still pursuing a high-school education (I.R.F.L.P. 120(a)). The Guidelines explicitly state that support for education beyond high school — including college — is not available under this rule.