Idaho child support calculator

Idaho works in marginal rates, the way income tax does. Rather than looking a dollar figure up in a schedule, the parents’ combined annual Guidelines Income is sliced into bands, and each band accrues support at its own declining percentage — for two children, 26% of the first $10,000, 25% of the next $10,000, 23% of the next, and so on down. Adding the bands gives the total both parents together owe each month, and each parent is responsible for the share matching their percentage of combined income.

Rule 120(i)(1) prints five rate tables, one for each number of children from one to five. Each has ten bands — five of $10,000 and five of $20,000 of combined annual Guidelines Income — followed by a final band at the same rate as the tenth. Every row prints its own per-month and per-year figure alongside the rate, so the table checks itself: rate × band reproduces both columns on all fifty rows. The four-child table’s final band is published as $20,000 where the others read $290,000, which ends that table at $170,000 of combined income rather than $440,000.

Idaho keeps child care and medical costs outside the basic figure. Work-related child care, health-insurance premiums and care the insurance does not cover are shared in proportion to Guidelines Income and, unless the parents agree otherwise, paid directly between them rather than folded into the support order. A single course of treatment costing the other parent more than $500 out of pocket needs written agreement or a prior court order. At the bottom of the scale, support should rarely be set at zero: there is a rebuttable presumption of at least $50 a month per child, and where the paying parent earns under $800 a month the court reviews both households closely so as not to deny a parent minimum subsistence.

Idaho’s threshold is 25% of overnights — about 91 nights a year. At or below that, the basic figure from the table stands, which is the case this calculator runs. Above it Idaho treats the arrangement as shared physical custody: the basic obligation is multiplied by 1.5 to reflect the real cost of running two homes, each parent’s share is worked out by income and then by the proportion of time the children spend with the other parent, and the two obligations are offset so only the difference is paid.

It runs the Rule 120 rate table band by band, splits the total by income share, shares child care and medical costs pro rata, and applies the $50-a-child presumptive minimum. It does not compute Guidelines Income from your pay stubs or apply the Rule 120(f) adjustments, run the shared- or split-custody calculations, impute income, apply the extended-visit reduction, or use the tax-benefit tables. For a figure you can file, use the Idaho child support worksheet or consult an attorney.