Idaho Child Support Calculator

Estimate Idaho child support for 2026 using the Income Shares guideline model under Idaho R. Civ. P. 120 (Idaho Child Support Guidelines). Enter both parents' incomes and the parenting-time split to see what you may owe or receive.

Idaho follows the Income Shares model under the Idaho Child Support Guidelines (Idaho Rule of Civil Procedure 120). The court combines both parents' monthly gross incomes, looks up the basic support obligation on the state's guideline schedule for that income level and number of children, then prorates the obligation between the parents according to each parent's percentage share of the combined income.

Idaho treats parenting time through a shared physical custody computation. When each parent has the child more than 25 percent of the year, the standard guideline math changes and a separate shared-care formula applies under the Idaho Child Support Guidelines. Below that threshold, the basic obligation is generally prorated by each parent's share of combined income without a parenting-time discount. The number on this page is an estimate, so confirm your overnight split on the official guideline worksheet.

In Idaho, the cost of the child's health insurance premium is added to the basic support obligation rather than ignored. Once added, that amount is shared between the parents in proportion to each parent's percentage of the combined gross income, the same way the base obligation is divided. The parent who actually pays the premium typically receives credit for it. This estimator approximates that, but the official Idaho worksheet controls the exact figure.

Work-related child care, such as daycare a parent needs in order to work, is added to the basic child support obligation under the Idaho Child Support Guidelines. After it is added, the cost is split between the parents according to each parent's percentage share of the combined gross income. Keep documentation of actual care costs, because the court bases the add-on on real, reasonable expenses rather than a flat amount.

Idaho judges start from the guideline amount produced under Idaho Rule of Civil Procedure 120, and that figure is presumed correct. A court may deviate when applying the guideline would be unjust or inappropriate for the specific family, and the parent asking for a different number must justify it on the record. The judge must make written findings explaining any deviation. This calculator shows the presumptive estimate only, so a magistrate's findings ultimately control.

Frequently asked questions

How is child support calculated in Idaho?

Idaho uses the Income Shares model under the Idaho Child Support Guidelines, found in Idaho Rule of Civil Procedure 120. The court adds both parents' monthly gross incomes together, looks up the basic support obligation on the state's guideline schedule for that combined income and the number of children, then divides that obligation between the parents based on each parent's percentage share of the combined income. Health insurance and work-related child care are added on top. Idaho Child Support Services helps administer and enforce orders. The number here is an estimate, and the official guideline form or a licensed attorney controls the final amount.

What is the official Idaho child support worksheet, and does it control my case?

Yes. Idaho's controlling form is the official child support worksheet tied to the Idaho Child Support Guidelines under Idaho Rule of Civil Procedure 120, available through the Idaho courts at isc.idaho.gov/icsg. That worksheet is the document the magistrate actually relies on, because it applies the Income Shares schedule, prorates the obligation by income share, and accounts for add-ons like health insurance and child care. The calculator on this page is a planning estimate to help you prepare. Before you file or rely on a number, complete the official worksheet or have a licensed Idaho attorney review it.

What income does Idaho count when figuring child support?

Idaho works from gross income from virtually any source. Under the Idaho Child Support Guidelines, that includes wages, self-employment earnings, retirement, unemployment benefits, workers' compensation, Social Security, bonuses, and recurring fringe benefits. For self-employed parents, reasonable business expenses can be deducted before the income figure is set. Because the calculation combines both parents' gross monthly incomes and then splits the obligation by each parent's share, an accurate income figure for both parents matters a great deal. This estimator uses the numbers you enter, so verify them against pay records and the official worksheet, which controls.

How does 50/50 or shared custody change child support in Idaho?

Shared physical custody can change the Idaho number significantly. When each parent has the child more than 25 percent of the year, the Idaho Child Support Guidelines trigger a separate shared-care computation instead of the standard formula. That separate math accounts for both households covering some of the child's costs directly. A 50/50 split does not automatically erase support, because the higher-earning parent often still pays something so the child's standard of living is similar in both homes. This page gives an estimate only, so run your actual overnight percentages through the official guideline worksheet.

Can a judge order a different amount than the Idaho guideline says?

Yes, but the guideline number under Idaho Rule of Civil Procedure 120 is presumed correct, so deviations are the exception. An Idaho magistrate may order a different amount when sticking to the guideline figure would be unjust or inappropriate given the family's specific situation. The parent who wants the court to depart from the guideline carries the burden of showing why, and the judge must put written findings in the record explaining the deviation. Because this estimator only shows the presumptive guideline number, the actual order can differ once a magistrate weighs the evidence and makes findings.

When does child support end in Idaho?

Idaho child support generally ends when the child turns 18. Unlike some states, Idaho does not automatically extend support to let a child finish high school, although parents can agree to continue support if they choose. Support can continue beyond age 18 for an adult child with a disability that began before the child reached majority. Because support does not stop on its own paperwork in every case, check the exact terms of your order. This page is informational only, and the official guideline form or an Idaho attorney governs your situation.

How do I change or enforce an Idaho child support order?

To change an order, you generally need a substantial and material change in circumstances. You can file a motion in the magistrate division of district court or request an administrative review through Idaho Child Support Services, and a recalculation under the Idaho Child Support Guidelines that produces a meaningful difference often qualifies. For enforcement, Idaho Child Support Services, part of the Department of Health and Welfare, uses immediate income withholding, tax refund offset, license suspension, lien filings, and contempt referrals. The estimate here helps you see whether a change may be worthwhile, but the official worksheet and the court control the result.