Idaho Child Support Calculator

Idaho uses the Income Shares Model under I.R.F.L.P. Rule 120, which combines both parents' gross monthly incomes and references the Basic Monthly Child Support Guidelines Schedule to determine a base obligation. Each parent's share is proportional to their percentage of combined income — if one parent earns 60% of the total, they pay 60% of the obligation. Health insurance, work-related childcare, and extraordinary medical expenses over $250 per child per year are added on top and split by the same income ratio.

Idaho uses 'ICSG Income' (Idaho Child Support Guidelines Income), which is gross income minus specific allowed deductions. Gross income includes wages, salaries, commissions, bonuses, overtime, tips, rental income, Social Security benefits, unemployment compensation, workers' compensation, disability and retirement benefits. Unlike many states, Idaho counts public assistance benefits received for the children as income. If a parent is voluntarily unemployed or underemployed, the court may impute income at approximately $15 per hour full-time.

When a child spends more than 25% of annual overnights with each parent, Idaho applies a shared custody adjustment under I.R.F.L.P. Rule 120. The base child support obligation is multiplied by 1.5, then each parent's share is calculated based on their income percentage and multiplied by the time the child spends with the other parent. The two amounts are offset, and the parent who owes more pays the difference. Below the 25% threshold, standard guidelines apply without adjustment.

Idaho allows child support modification when there is a substantial and material change in circumstances under Idaho Code § 32-709. Common grounds include significant income changes, job loss, changes in custody time, or a child's increased needs such as medical expenses. The court recalculates using current incomes and the guidelines schedule. Notably, children born or adopted after the existing order was entered are not considered when a parent requests modification.

Beyond the base guideline amount, Idaho requires three mandatory add-on expenses shared proportionally by income: health insurance premiums for the children, work-related childcare costs necessary for employment or job training, and extraordinary uninsured medical expenses exceeding $250 per child per year. The base obligation itself covers ordinary costs including housing, food, clothing, transportation, and entertainment based on economic data about typical spending in intact families at comparable income levels.

Idaho presumes a minimum contribution of $50 per month per child, and courts should only rarely set child support at zero. When the paying parent's monthly income falls below $800, the judge must carefully review both parents' incomes and expenses to ensure the order does not deny the parent minimum self-support. The guidelines schedule covers combined annual incomes up to $440,000. Above that cap, courts have discretion to award additional support considering the child's financial needs, pre-divorce standard of living, and special circumstances under Idaho Code § 32-706.

Under Idaho Code § 32-706, child support continues until the child reaches age 18. If the child is still attending high school after turning 18, the court may order support to continue until the child finishes high school or reaches age 19, whichever comes first. Idaho does not require parents to pay for college expenses. Support obligations also end if the child marries, is legally emancipated, or enters active military duty before age 18.

Idaho enforces child support through mandatory income withholding under Idaho Code Title 32, Chapter 12. All child support orders include automatic income withholding provisions notifying the obligor of enforcement. Additional enforcement tools include interception of tax refunds, suspension of driver's and professional licenses, liens on real and personal property, passport denial for arrears exceeding $2,500, and contempt of court proceedings that can result in fines or jail time. The Idaho Department of Health and Welfare's Child Support Services division assists with enforcement.