Idaho Child Support Guidelines

Idaho calculates child support using the income shares model, which is based on the principle that children should receive the same proportion of parental income they would have received if their parents lived together. The Idaho Child Support Guidelines, codified under Idaho Rules of Family Law Procedure Rule 120 (IRFLP 120), provide a structured formula for determining each parent’s obligation based on combined parental income, the number of children, and time-sharing arrangements.

Understanding how the guidelines work is essential for any parent going through a divorce, separation, or paternity action in Idaho. This article explains each step of the calculation, the factors that can lead to adjustments, and the process for modifying an existing order.

For a national overview of how child support works, see our guide on how child support is calculated.

How the Income Shares Model Works

The income shares model starts from the idea that children should not suffer a lower standard of living because their parents live apart. The model estimates what both parents would have spent on the child if the family were intact, then allocates that amount proportionally based on each parent’s income.

The basic steps are:

1. Calculate each parent’s gross monthly income
2. Combine both parents’ gross incomes
3. Look up the basic child support obligation on the guideline table based on combined income and number of children
4. Determine each parent’s percentage share of the combined income
5. Allocate the basic child support obligation proportionally
6. Add adjustments for healthcare, childcare, and shared custody time

The parent who spends less time with the child—or the parent with the higher income share—typically pays child support to the other parent.

Gross Income Definition

Under the Idaho Child Support Guidelines, gross income is defined broadly. It includes virtually all income from any source, whether earned or unearned. Specific categories include:

• Salaries, wages, bonuses, and commissions
• Self-employment income (gross receipts minus ordinary and necessary business expenses)
• Workers’ compensation benefits
• Unemployment insurance benefits
• Disability insurance benefits and Social Security disability
• Pension and retirement income
• Annuities
• Trust income
• Capital gains
• Spousal support (alimony) received
• Rental income
• Dividends and interest
• Any other money received on a regular basis

Income that is excluded from the calculation includes means-tested public assistance (such as TANF, food stamps, and Supplemental Security Income) and child support received for other children.

The Guideline Table

The Idaho Child Support Guidelines include a basic child support obligation table that specifies the combined child support obligation based on the parents’ combined gross income and the number of children. The table covers combined monthly incomes from $800 up to $20,000, with six columns for one through six children.

For combined incomes above the table’s range, the court exercises discretion in setting the support amount, considering the child’s needs and the standard of living the child would have enjoyed had the family remained intact.

For combined incomes below $800 per month, the guidelines provide a minimum support obligation to ensure that some support is paid regardless of income level. The minimum monthly obligation in Idaho is $50 per child.

Proportional Allocation Between Parents

Once the basic child support obligation is determined from the table, it is divided between the parents in proportion to their share of the combined gross income.

For example, if Parent A earns $4,000 per month and Parent B earns $6,000 per month, their combined income is $10,000. Parent A’s share is 40%, and Parent B’s share is 60%. If the guideline table specifies a basic child support obligation of $1,200 for two children at that income level, Parent A’s share is $480 (40%) and Parent B’s share is $720 (60%).

The parent with whom the child primarily resides is presumed to spend their share directly on the child. The other parent pays their share to the custodial parent as child support.

Healthcare and Childcare Add-Ons

In addition to the base child support obligation, Idaho requires certain costs to be allocated between the parents:

Health insurance premiums. The cost of adding the child to a parent’s health insurance plan is divided proportionally between the parents based on their income shares. If neither parent has access to employer-provided insurance at a reasonable cost, the court determines how coverage will be obtained and paid for.

Unreimbursed medical expenses. Out-of-pocket medical, dental, orthodontic, vision, and prescription costs not covered by insurance are divided between the parents in proportion to their income shares. The guidelines require that the first $250 per child per year in unreimbursed medical expenses be covered by the custodial parent before the sharing obligation begins.

Work-related childcare costs. Daycare, after-school care, and other childcare expenses incurred because a parent is working, seeking employment, or attending school are added to the calculation and divided proportionally. These costs must be reasonable and necessary.

These add-ons can significantly increase the total child support obligation, especially for families with young children requiring full-time childcare or children with significant medical needs.

Shared Custody Adjustments

When both parents have substantial time with the child, the child support calculation is adjusted to reflect the direct costs each parent incurs during their parenting time.

Under Idaho’s guidelines, a shared custody adjustment applies when the non-custodial parent exercises 25% or more of the overnights in a year (approximately 91 or more overnights). The adjustment formula accounts for the fact that the non-custodial parent bears direct housing, food, and other expenses during their parenting time.

The shared custody calculation works by:

1. Calculating each parent’s basic child support obligation based on their income share
2. Multiplying each parent’s obligation by 1.5 to create an adjusted figure
3. Applying each parent’s percentage of overnights
4. Offsetting the two figures to determine the net child support obligation

The result is a sliding scale—the more overnights the paying parent exercises, the lower the child support payment. At equal time-sharing (50/50), the higher-earning parent still pays support to the lower-earning parent, but the amount is reduced compared to a traditional custody arrangement.

Deviation Factors

The guideline amount is presumed correct, but the court can deviate if applying the guidelines would be unjust or inappropriate. Factors include extraordinary medical expenses, special educational needs, the child’s independent income, custody arrangements not adequately addressed by the standard adjustment, tax considerations, and the standard of living the child would have enjoyed had the family remained intact.

A parent seeking a deviation must present supporting evidence, and the court must make written findings explaining the deviation.

Self-Employment Income

Self-employment income is calculated as gross receipts minus ordinary and necessary business expenses. The court examines business expenses carefully to prevent a parent from artificially reducing income through excessive deductions.

Courts pay close attention to depreciation (which reduces taxable income but does not represent actual cash spent), personal expenses claimed as business deductions, inconsistent income (which may be averaged over several years), and unreported cash income. The court may impute income if the evidence shows a self-employed parent is underreporting earnings.

Imputing Income

When a parent is voluntarily unemployed or underemployed, the court may impute income—calculating child support based on what the parent could earn, not what they actually earn. The court considers the parent’s work history, education, occupational qualifications, the prevailing job market, and physical and mental health.

Income is not imputed to a parent who is unable to work due to a legitimate disability, who is caring for a young child, or who is making a good-faith effort to find employment.

Modification of Child Support

Either parent can request a modification when there has been a substantial and material change in circumstances. A change is presumed substantial if the recalculated amount differs from the existing order by 15% or more.

Common triggers include a significant income change, a change in parenting time, changes in the child’s healthcare or childcare needs, or emancipation of a child on the order. The parent requesting modification must file a motion and provide updated financial information.

For more on the modification process, see our guide on how to modify child support.

Enforcement

When a parent fails to pay court-ordered child support, Idaho provides enforcement mechanisms through the Idaho Department of Health and Welfare, Child Support Services, including income withholding, tax refund interception, license suspension, contempt of court proceedings, credit reporting, and property liens.

For more on enforcement options, see our guide on child support enforcement.

What to Do Next

If you are involved in a child support matter in Idaho, take these steps:

1. Gather income documentation. Collect recent pay stubs, tax returns, bank statements, and records of all income sources. Accurate income information is the foundation of the child support calculation.
2. Track parenting time. The number of overnights each parent exercises directly affects the child support amount under the shared custody adjustment. Keep accurate records of your actual parenting schedule.
3. Document add-on expenses. Maintain records of health insurance premiums, childcare costs, and unreimbursed medical expenses. These costs are divided between parents as part of the support calculation.
4. Understand your rights. If the other parent is voluntarily underemployed or not disclosing income, you can ask the court to impute income based on earning capacity.
5. Consult an Idaho family law attorney. Child support calculations involve multiple variables, and the financial stakes are significant for both parents and children. Schedule a free consultation to ensure your child support is calculated correctly under Idaho law.

Frequently Asked Questions

How is child support calculated in Idaho?

Idaho uses the income shares model. Both parents’ gross incomes are combined, and the basic child support obligation is determined from a guideline table based on combined income and the number of children. Each parent’s share is allocated proportionally based on their percentage of the combined income. Adjustments are made for healthcare, childcare, and shared parenting time.

What is the minimum child support in Idaho?

The Idaho Child Support Guidelines establish a minimum child support obligation of $50 per child per month, regardless of the obligor’s income level. This ensures that some support is paid even in low-income situations.

Can Idaho child support be modified?

Yes. Either parent can request a modification when there has been a substantial and material change in circumstances. A change is presumed to be substantial if the recalculated support amount differs from the existing order by 15% or more. Common triggers include significant income changes, changes in custody time, or changes in the child’s needs.

How does shared custody affect child support in Idaho?

When the non-custodial parent has 25% or more of overnights (91 or more nights per year), the shared custody adjustment applies. This adjustment reduces the child support obligation to account for the direct expenses the non-custodial parent incurs during their parenting time. The more overnights the paying parent exercises, the lower the support amount.

What happens if a parent does not pay child support in Idaho?

Idaho has robust enforcement mechanisms, including automatic income withholding, tax refund interception, license suspension, contempt of court proceedings, credit reporting, and property liens. The Idaho Department of Health and Welfare, Child Support Services administers enforcement actions.