Support in Idaho (2026)

Idaho’s Income Shares Model for Child Support

Idaho uses an income shares model established under the Idaho Child Support Guidelines (Idaho Rules of Civil Procedure, Rule 126). The model is based on the economic principle that children should receive the same proportion of parental income they would have received had the family remained intact. Idaho’s guidelines are adopted by the Idaho Supreme Court rather than by the legislature, which means updates follow the court’s rulemaking process rather than requiring a new statute.

The calculation works as follows:

1. Determine gross income. Each parent’s gross income is calculated, including wages, salaries, commissions, bonuses, self-employment income, Social Security benefits, workers’ compensation, unemployment compensation, pensions, dividends, interest, trust income, rental income, and other recurring earnings. Courts may impute income to a parent who is voluntarily unemployed or underemployed without reasonable cause.
2. Apply adjustments. Certain deductions are made, including taxes and pre-existing child support or spousal maintenance obligations.
3. Combine incomes. The parents’ adjusted incomes are combined.
4. Look up the obligation. The guidelines schedule identifies the basic support obligation based on the combined income and the number of children.
5. Apportion proportionally. Each parent’s share of the obligation is proportional to their percentage of the combined income. Work-related child care costs and health insurance premiums for the child are added and apportioned similarly.

For a general overview of income shares models, see our guide on how child support is calculated. You can also estimate your potential obligation with our child support calculator.

Fault and Its Role in Maintenance (but Not Child Support)

An important distinction in Idaho’s support framework is the role of marital fault. Fault plays no role in child support calculations — the guidelines are purely mathematical and income-based. However, fault is an explicit factor in spousal maintenance determinations under Idaho Code Section 32-705. A spouse whose misconduct contributed to the breakdown of the marriage may receive a less favorable maintenance outcome. This makes Idaho unusual among western states, where fault-based considerations in support are increasingly rare.

Deviations from the Child Support Guidelines

The Idaho guidelines create a rebuttable presumption that the calculated amount is correct. However, the court may deviate from the guidelines if strict application would be unjust or inappropriate. Recognized grounds for deviation include:

• Shared or split physical custody arrangements
• Extraordinary medical expenses not covered by insurance
• Extraordinary educational expenses
• The needs of other dependents of either parent
• Tax planning considerations that benefit the child
• Any other factor the court deems relevant to the best interests of the child

Any deviation must be accompanied by a written finding explaining why the guidelines amount is inappropriate.

Duration of Child Support

Child support in Idaho generally continues until the child turns 18, or until age 19 if the child is still attending high school. Support terminates upon the child’s marriage, emancipation, or entry into military service. Idaho courts do not typically order parents to pay for post-secondary education expenses — a distinction from states like Hawaii, which may extend support through age 23 for college students.

Modifying Child Support

Either parent may petition for modification by demonstrating a material and substantial change of circumstances that is permanent and relates to the needs of the child or the ability of either parent to pay. Idaho also allows modification when the existing order deviates significantly from the current guidelines amount.

Any modification takes effect from the date the petition is filed. Arrearages that accrued before the filing date accrue interest and cannot be retroactively reduced.

Enforcement of Child Support Orders

Idaho’s Department of Health and Welfare, through the Child Support Program, and the courts enforce child support orders through multiple methods:

• Income withholding from wages
• Interception of state and federal tax refunds
• Suspension of driver’s licenses and professional or recreational licenses
• Liens on real and personal property
• Contempt of court proceedings
• Passport denial for arrearages exceeding $2,500
• Credit bureau reporting

Idaho participates in interstate enforcement through the Uniform Interstate Family Support Act (UIFSA) for cases involving parents in different states.

Spousal Maintenance in Idaho

Idaho law authorizes spousal maintenance under Idaho Code Section 32-705 but does not use a formula to calculate it. The court exercises broad discretion, and maintenance is available only when the requesting spouse demonstrates both a need for support and a lack of sufficient property to provide for their own reasonable needs.

The primary types of maintenance include:

• Temporary maintenance. Support during the pendency of the divorce proceedings.
• Rehabilitative maintenance. Support for a defined period to allow a spouse to acquire education, training, or work experience to become self-supporting.
• Transitional maintenance. Short-term support to help a spouse adjust to post-divorce financial circumstances.
• Permanent maintenance. Ongoing support in cases where the spouse cannot become self-supporting due to age, health, or other factors, typically awarded after long marriages.

Factors in Maintenance Determinations

Idaho courts consider the following factors under Idaho Code Section 32-705:

• The financial resources of the party seeking maintenance, including marital property apportioned to that party
• The time necessary to acquire education or training for appropriate employment
• The duration of the marriage
• The age and physical and emotional condition of the spouse seeking maintenance
• The ability of the other spouse to meet their own needs while paying maintenance
• The tax consequences to each party
• The fault of either party

Community Property and Its Effect on Maintenance

Because Idaho is a community property state, the property division stage of a divorce directly affects whether maintenance is warranted. After community property is divided substantially equally under Idaho Code Section 32-712, the court evaluates whether the requesting spouse’s share of the property — combined with their earning capacity — is sufficient to meet reasonable needs. If the property division adequately provides for both parties, maintenance may not be necessary. This interplay between property division and maintenance is a distinctive feature of divorce in community property states.

When to Seek Legal Guidance

Idaho’s income shares model for child support and its discretionary approach to spousal maintenance both involve fact-intensive analyses that benefit from professional guidance. The role of fault in maintenance determinations and the community property framework’s effect on the overall support picture add layers of complexity. If you are evaluating a child support calculation or considering a maintenance claim, schedule a free consultation with an experienced Idaho family law attorney.

Statutes referenced: Idaho Rules of Civil Procedure Rule 126 (child support guidelines); Idaho Code Sections 32-705 through 32-709 (spousal maintenance); Idaho Code Section 32-712 (community property division).

Frequently Asked Questions

How is child support calculated in Idaho?

Idaho uses the income shares model under the Idaho Child Support Guidelines (Rule 126 of the Idaho Rules of Civil Procedure). Both parents’ gross incomes are combined and applied to the guidelines schedule, which identifies a basic support obligation based on combined income and number of children. Each parent’s share is proportional to their percentage of the combined income. Childcare costs and health insurance premiums are added and apportioned similarly.

How long does child support last in Idaho?

Child support in Idaho generally continues until the child turns 18, or until age 19 if the child is still attending high school. Support also terminates upon the child’s marriage, emancipation, or entry into military service. Idaho courts do not typically order parents to pay for post-secondary education.

Can fault affect spousal maintenance in Idaho?

Yes. Under Idaho Code Section 32-705, fault in the breakdown of the marriage is one of the factors courts may consider when determining maintenance, along with the duration of the marriage, financial resources, age, health, and the time needed for the requesting spouse to acquire education or training. Fault is not necessarily dispositive but it is part of the analysis.

What is the standard for modifying child support in Idaho?

Either parent may petition for modification by showing a material and substantial change of circumstances that is permanent and relates to the child’s needs or either parent’s ability to pay. Idaho also allows modification when the existing order deviates significantly from the current guidelines amount.

How does community property affect spousal maintenance in Idaho?

After community property is divided substantially equally, the court evaluates whether the requesting spouse’s share — combined with their earning capacity — is sufficient for reasonable needs. If the property division adequately provides for both parties, maintenance may be reduced or denied. This interplay is a distinctive feature of divorce in community property states like Idaho.

How This Guide Was Researched

This guide was developed by reviewing the Idaho Child Support Guidelines (Idaho Rules of Civil Procedure, Rule 126), Idaho Code Sections 32-705 through 32-709 (spousal maintenance), and the Idaho Supreme Court’s child support guidelines worksheets. Enforcement procedures were verified against Idaho Department of Health and Welfare Child Support Program publications. The analysis of fault’s role in maintenance was informed by Idaho State Bar family law section resources and Idaho appellate case law.

Sources and Legal References

This guide draws on the following specific legal authorities and resources:

• Idaho Rules of Civil Procedure, Rule 126 — Idaho Child Support Guidelines (income shares model, guidelines schedule, and deviation factors)
• Idaho Code Section 32-705 — Spousal maintenance eligibility and factors (including fault)
• Idaho Code Sections 32-705 through 32-709 — Full spousal maintenance framework
• Idaho Code Section 32-712 — Community property division upon divorce
• Idaho Department of Health and Welfare — Child Support Program enforcement procedures

Official Idaho Resources

• Idaho Supreme Court — Family Court Services
• Idaho Rules of Family Law Procedure
• Idaho Department of Health and Welfare — Child Support

For more about how we research our guides, see our editorial policy and sources methodology.

Related Guides

• Child custody in Idaho
• Divorce in Idaho
• How child support is calculated
• How alimony works
• Modifying child support
• Child support enforcement
• Community property vs. equitable distribution
• Property division in divorce