Idaho uses an income shares model per IRFLP Rule 120/126 (updated July 1, 2025). Uses GROSS monthly income. $440,000 combined annual income cap. Minimum: $50/child/month.
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Idaho calculates child support using the Income shares using GROSS monthly income established under IRFLP Rule 120/126 (updated July 1, 2025). This is a statutory formula that leaves limited room for judicial discretion on the base calculation amount, ensuring consistency and predictability for families across the state.
Total obligation from schedule x obligor income share %.
The calculation begins with determining each parent's net disposable income, which includes virtually all sources of income minus taxes, mandatory payroll deductions, and certain hardship deductions. The court then applies the statutory formula using the time each parent has primary physical responsibility for the children and the applicable income allocation brackets.
Beyond the base formula amount, Idahorequires additional contributions for mandatory add-on expenses. These typically include childcare costs necessary for the custodial parent's employment or education, uninsured healthcare expenses for the children, and in some cases, educational and travel costs. These add-ons are split between parents in proportion to their respective incomes.
Primary statute: IRFLP Rule 120/126 (updated July 1, 2025)
Income shares model using GROSS monthly income.
$440,000 combined annual income cap.
Minimum: $50/child/month.
Approximate: 1 child ~18%, 2 ~27%, 3 ~32%.
Schedule values are APPROXIMATIONS.
Uses GROSS income (not net).
Idaho is COMMUNITY PROPERTY (9th of 9).
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Residency Requirement
6-week residency (§32-701)
Mandatory Waiting Period
21-day waiting period after filing
No-Fault Ground
Irreconcilable differences. Fault grounds also available.
State Income Tax
Flat 5.3% (HB 40, March 2025).
Idaho uses the Income shares using GROSS monthly income under IRFLP Rule 120/126 (updated July 1, 2025). Idaho uses an income shares model per IRFLP Rule 120/126 (updated July 1, 2025). Uses GROSS monthly income. $440,000 combined annual income cap. Minimum: $50/child/month.
Key factors include both parents' income, the number of children, custodial time share, mandatory add-on expenses (childcare, health insurance), and any applicable deductions. Income shares model using GROSS monthly income.
Yes. Either parent can request a modification if there has been a material change in circumstances, such as a significant change in income, custody arrangements, or the needs of the child. The court will recalculate support using the same statutory formula.
Total obligation from schedule x obligor income share %.
Get a personalized child support calculation based on Idaho's actual statutory formula.
Start My Free IdahoEstimate →This tool provides educational estimates based on Idaho family law and does not constitute legal advice. Child support calculations are approximations of the statutory formula and may differ from court-ordered amounts. Consult a licensed Idaho family law attorney before making decisions. Primary statute: IRFLP Rule 120/126 (updated July 1, 2025).