Montana Child Support Calculator (2025)

How Montana Calculates Child Support

Montana uses the Income Shares model for calculating child support, governed by ARM 37.62.106 (Administrative Rules of Montana). This approach is based on the economic principle that children should receive the same proportion of parental income they would have received if both parents lived together in a single household. Montana adopted the Income Shares model because it considers both parents' financial contributions, creating a more equitable outcome for families.

The Montana child support calculation begins by determining each parent's gross income from all sources. Allowable deductions are then subtracted to arrive at each parent's adjusted gross income. The two adjusted incomes are combined and cross-referenced against the Montana child support schedule, which provides the basic child support obligation based on the combined income level and the number of children requiring support. Each parent is then responsible for a proportionate share of this obligation, determined by their percentage contribution to the combined income.

Montana's guidelines also incorporate adjustments for parenting time, recognizing that the non-custodial parent incurs direct costs when the children are in their care. When the non-custodial parent exercises more than 110 overnight visits per year, the guidelines provide a reduction in the support amount to account for duplicated housing, food, and related expenses during those periods. This parenting time adjustment is one of the key features that distinguishes Montana's implementation from some other Income Shares states.

History and Development of Montana Child Support Guidelines

Montana's child support guidelines have evolved significantly since they were first established. The current framework under ARM 37.62.106 reflects years of research, public input, and legislative refinement. The Montana Department of Public Health and Human Services (DPHHS) Child Support Enforcement Division (CSED) is the primary agency responsible for administering the guidelines and enforcing child support orders statewide. Montana reviews its guidelines regularly to ensure they remain consistent with current economic data on the costs of raising children, as required by federal mandates under Title IV-D of the Social Security Act.

The state's commitment to fairness in child support is evidenced by the detailed nature of the guidelines, which address not only basic support obligations but also health insurance costs, childcare expenses, and other extraordinary costs. Montana courts have consistently upheld the guidelines as producing fair results in the vast majority of cases, while also providing judicial discretion to deviate when circumstances warrant a different outcome.

Understanding ARM 37.62.106

ARM 37.62.106 is the specific administrative rule that establishes Montana's child support guidelines. The rule is part of a broader set of administrative rules (ARM Title 37, Chapter 62) that govern child support proceedings in Montana. ARM 37.62.106 specifically addresses the calculation methodology, income definitions, allowable deductions, the support schedule, and the process for determining each parent's financial obligation.

The rule establishes a rebuttable presumption that the guideline amount is the correct amount of child support. This means courts must follow the guidelines unless a party presents evidence that applying them would be unjust or inappropriate in the specific circumstances of the case. When deviating from the guidelines, courts are required to make written findings explaining the reasons for the deviation and the amount that would have been calculated under the guidelines.

Who Must Follow ARM 37.62.106?

The Montana child support guidelines apply to all child support proceedings in the state, including initial determinations in divorce cases, paternity actions, modifications of existing orders, and cases administered through the CSED. Even when parents reach a private agreement on child support, the agreement must be reviewed against the guideline amount, and any significant deviation requires court approval with written justification.

The Montana Child Support Worksheets

Montana uses standardized worksheets for calculating child support. The primary worksheet requires both parents to disclose all sources of income and allowable deductions. The worksheet then guides the calculation through each step: determining adjusted gross income, combining incomes, looking up the basic obligation, calculating each parent's percentage share, applying parenting time adjustments, and allocating additional expenses. These worksheets must be filed with the court in all child support proceedings to ensure transparency and consistency in calculations.

The Income Shares Model in Montana

The Income Shares model used in Montana is based on decades of economic research showing that in intact two-parent families, both parents contribute financially to their children's needs. When parents separate, the Income Shares model attempts to maintain the same level of financial support for the children by determining what both parents would have contributed had they remained together.

Montana's implementation of the Income Shares model is comprehensive, accounting for both parents' full financial picture. The combined income approach ensures that children benefit from both parents' earning capacity, rather than being limited to a percentage of only one parent's income. This produces more equitable results and better reflects the economic reality of child-rearing costs in Montana.

Why Montana Uses Income Shares

Montana selected the Income Shares model because it produces outcomes that most closely replicate the economic support children would receive in an intact household. Economic studies from the U.S. Department of Agriculture (USDA) and other research institutions have provided the data underlying the support schedules. These studies measure actual expenditures on children at various income levels, accounting for housing, food, clothing, transportation, healthcare, education, and miscellaneous costs. Montana's schedule reflects this research, adjusted for cost-of-living factors specific to the state.

The Income Shares approach also aligns with Montana's public policy goals of ensuring that both parents bear financial responsibility for their children. By considering both incomes, the model prevents situations where one parent bears a disproportionate share of child-rearing costs while the other parent contributes nothing. This balanced approach has been upheld by Montana courts as fair and consistent with the best interests of children.

Gross Income and Allowable Deductions

Montana's child support guidelines define gross income broadly to capture the full financial picture of each parent. Understanding what qualifies as income and what deductions are permitted is essential for an accurate child support calculation.

What Counts as Gross Income in Montana

Under ARM 37.62.106, gross income includes virtually all forms of compensation and financial benefits received by a parent. Montana courts look at the totality of a parent's financial resources when determining income for child support purposes:

• Wages and salaries from all employment, including regular pay, overtime, tips, and shift differentials
• Commissions and bonuses received from employment, typically averaged over a reasonable period
• Self-employment income after legitimate business expenses but before personal income taxes
• Rental and real property income after reasonable operating expenses
• Interest and dividends from investments, savings, and financial instruments
• Pension and retirement distributions including regular and lump-sum payments
• Social Security benefits including retirement, disability, and survivor benefits
• Workers' compensation benefits
• Unemployment insurance benefits
• Alimony received from another relationship
• Trust income and distributions from trusts or estates
• Capital gains from the sale of property or investments
• Severance pay and termination benefits
• Military pay including base pay, BAH, BAS, and special duty pay
• Annuity payments and insurance proceeds

Allowable Deductions in Montana

Montana permits certain deductions from gross income to arrive at the adjusted gross income used in the support calculation. These deductions recognize that some portions of a parent's income are unavailable for child support purposes:

• Federal and Montana state income taxes based on the appropriate filing status
• FICA taxes (Social Security and Medicare contributions)
• Mandatory retirement contributions required as a condition of employment
• Mandatory union dues required for employment
• Pre-existing child support obligations paid under a court order for other children
• Alimony paid under a court order to a former spouse
• Self-employment tax (the employer-equivalent portion of FICA)

Imputed Income in Montana

Montana courts can impute income to a parent who is found to be voluntarily unemployed or underemployed. The court examines the parent's education, work history, job skills, and the local labor market to determine what the parent could reasonably earn. Income imputation is designed to prevent parents from deliberately reducing their income to lower their child support obligation. However, Montana courts will not impute income when a parent's unemployment or underemployment is due to legitimate reasons such as disability, caregiving responsibilities for a young child, pursuing education that will increase earning capacity, or inability to find work despite diligent efforts.

The burden of proof regarding imputed income depends on the circumstances. If one parent alleges that the other is voluntarily underemployed, that parent typically must present evidence supporting the claim. The allegedly underemployed parent then has the opportunity to present evidence showing legitimate reasons for their current income level. Montana courts consider these matters on a case-by-case basis, giving weight to all relevant factors.

The Montana Support Schedule

The Montana child support schedule is the reference table used to determine the basic child support obligation based on the parents' combined adjusted gross monthly income and the number of children. The schedule covers a wide range of income levels and is based on economic data about the actual costs of raising children at various income levels in Montana.

Below is a representative sample of the Montana child support schedule showing basic monthly obligations. The actual schedule contains many more entries with finer income increments:

The schedule amounts increase as combined income rises, but at a decreasing rate. This reflects the economic reality that while higher-income families spend more on their children in absolute terms, the percentage of income devoted to child-rearing decreases as income grows. For combined incomes exceeding the schedule maximum, Montana courts typically extrapolate using the percentage at the highest scheduled level or exercise judicial discretion based on the children's established standard of living.

How to Read the Schedule

To use the Montana schedule, locate the row corresponding to the parents' combined adjusted gross monthly income. If the exact amount is not listed, interpolate between the two nearest values for a more precise figure. Then read across to the column for the appropriate number of children. The resulting figure is the basic child support obligation that will be divided between the parents in proportion to their income shares.

Parenting Time Adjustments

Montana's child support guidelines include a meaningful adjustment for parenting time (also called visitation or custody time). The guidelines recognize that when the non-custodial parent spends significant time with the children, they incur direct costs for housing, food, transportation, activities, and other necessities during those periods. Without a parenting time adjustment, the non-custodial parent would effectively pay twice for those expenses: once through child support and again through direct spending during their parenting time.

Under Montana's guidelines, the parenting time adjustment applies when the non-custodial parent has more than 110 overnights per year (approximately 30% of the year). The adjustment reduces the basic support obligation proportionally based on the number of overnights. This threshold recognizes that minimal or standard visitation does not create sufficient duplicated costs to warrant an adjustment.

The Parenting Time Adjustment Formula

Montana uses the following approach for calculating the parenting time adjustment:

1. Determine the non-custodial parent's annual overnights with the children
2. If the overnights exceed 110, calculate the percentage of time: overnights divided by 365
3. Apply the adjustment multiplier: (1 - 2 x percentage of time with NCP)
4. Multiply the non-custodial parent's basic obligation share by this multiplier
5. The result is the adjusted support amount owed by the non-custodial parent

For equal custody arrangements (approximately 182.5 overnights each), the formula produces a significantly reduced obligation that reflects the near-equal sharing of direct costs. In these situations, the higher-income parent typically pays a reduced amount to the lower-income parent to equalize the children's standard of living between the two households.

Counting Overnights in Montana

Montana courts count overnights based on the parenting plan or custody order. Overnights include any night the child sleeps at the non-custodial parent's residence, whether during regular visitation, holidays, summer breaks, or special occasions. If parents have different custody arrangements for different children, the overnights may be calculated separately for each child. Courts typically look at the court-ordered schedule rather than actual practice, unless there is a significant and consistent deviation from the order.

When Courts Deviate from Guidelines

While Montana's child support guidelines create a presumption that the calculated amount is appropriate, courts retain the authority to deviate when applying the guidelines would produce an unjust or inappropriate result. Deviations require specific written findings from the court explaining why the guideline amount is not appropriate and what amount is being ordered instead.

Common grounds for deviation from Montana's child support guidelines include:

• Extraordinary medical expenses for a child with chronic health conditions or disabilities that substantially exceed what the guidelines contemplate
• Special educational needs requiring private schooling, tutoring, or specialized programs
• Seasonal or irregular income that makes the standard monthly calculation unreliable, common in Montana's agriculture, tourism, and natural resource sectors
• Long-distance travel expenses for exercising parenting time, which can be substantial in Montana given the state's vast geographic area and rural character
• Combined income exceeding the schedule maximum requiring judicial determination of appropriate support
• The child's independent financial resources including trust income, inheritance, or the child's own earnings
• Extraordinary expenses for extracurricular activities that benefit the child's development
• Tax consequences that create inequitable results under the standard calculation
• Shared custody arrangements that do not fit neatly within the standard parenting time adjustment

Montana courts approach deviations cautiously. The party seeking the deviation bears the burden of demonstrating that the guideline amount would be unjust or inappropriate. Courts must balance the children's needs against the parents' ability to pay, always keeping the best interests of the child as the paramount consideration.

How to Modify Child Support in Montana

Montana allows modification of child support orders when there has been a material change in circumstances since the last order was established or modified. Under Montana law, a material change is presumed when applying the current guidelines to the current financial situation would result in a support amount that differs by at least 25% or $50 per month (whichever is less) from the existing order.

Common grounds for seeking a child support modification in Montana include:

• Significant change in either parent's income due to job change, promotion, demotion, or economic conditions
• Job loss or involuntary reduction in work hours
• Change in custody or parenting time arrangement
• A child reaching the age of majority or becoming emancipated, potentially reducing the number of children covered by the order
• Change in the child's needs such as developing a medical condition or disability
• Significant change in health insurance costs
• Change in childcare expenses as children enter school
• Incarceration of the paying parent (Montana courts consider this differently than voluntary unemployment)

The Modification Process in Montana

To modify child support in Montana, you can either file a petition with the district court that issued the original order or request a review through the Montana CSED if your case is administered through the agency. The CSED conducts periodic reviews of child support orders and will initiate modifications when warranted. For private modifications, you must file the petition, serve the other parent, provide updated financial information, and attend a hearing. The court will then determine whether a modification is appropriate based on the evidence presented.

Modifications in Montana are generally effective from the date the petition is filed or the review is initiated, not retroactively. This means parents who experience a change in circumstances should seek modification promptly. The existing order remains in full force until officially modified by the court, so continued payment at the current level is required regardless of changed circumstances until a new order is entered.

Enforcement of Montana Child Support

Montana takes child support enforcement seriously, employing a comprehensive set of tools to ensure compliance with support orders. The Montana CSED is the primary enforcement agency, working in coordination with the court system and federal agencies to collect child support from non-paying parents.

Enforcement mechanisms available in Montana include:

• Income withholding: Automatic deduction of child support from the non-custodial parent's wages, the most common and effective collection method
• Tax refund interception: Both Montana state and federal tax refunds can be intercepted to satisfy past-due child support
• License suspension: Driver's licenses, professional licenses, hunting licenses, and fishing licenses can be suspended for non-payment
• Contempt of court: Parents who willfully refuse to pay can be held in contempt, potentially resulting in fines or jail time
• Property liens: Liens can be placed on real estate, vehicles, and other significant assets
• Bank account levies: Funds in bank accounts can be seized to satisfy arrearages
• Credit reporting: Delinquent child support is reported to credit bureaus, impacting credit scores
• Passport denial: Parents owing more than $2,500 in past-due support may be denied or have their passport revoked
• Workers' compensation and unemployment interception: These benefits can be intercepted for child support

Montana participates in the Uniform Interstate Family Support Act (UIFSA), enabling enforcement of Montana child support orders in other states and enforcement of other states' orders in Montana. The state also uses the Federal Parent Locator Service to find non-paying parents who have moved across state lines. Montana's enforcement record is consistently among the better-performing states nationally, with high collection rates attributed to aggressive use of automated enforcement tools.

Interest on Arrearages in Montana

Under Montana law, past-due child support accrues interest at the rate of 10% per year. This interest is calculated on the unpaid balance from the date each payment becomes due. The substantial interest rate serves as a deterrent against non-payment and ensures that delayed payments carry a financial penalty. Parents who fall behind on child support should understand that their arrearages will grow over time due to interest, making it increasingly important to seek modification promptly if they are unable to pay the current amount.

Montana Child Support and Taxes

Understanding the tax implications of child support is important for both paying and receiving parents in Montana. Under current federal tax law, child support payments are neither taxable income to the recipient nor tax-deductible for the payer. This treatment has been consistent under federal law and is not affected by Montana state tax law.

Key tax considerations for Montana child support include:

• Dependency exemptions: The custodial parent generally claims the child as a dependent for tax purposes. However, parents can agree (or the court can order) that the non-custodial parent claims the exemption, using IRS Form 8332.
• Child tax credit: The parent claiming the child as a dependent can claim the child tax credit, worth up to $2,000 per qualifying child.
• Earned Income Tax Credit (EITC): The custodial parent may qualify for the EITC based on income and qualifying children.
• Head of household filing status: The custodial parent typically qualifies for the more advantageous head of household filing status.
• Medical expense deductions: Either parent can deduct medical expenses they pay for the child, subject to the AGI threshold.
• Montana state tax: Montana does not provide a separate state tax deduction for child support payments, consistent with federal treatment.

Montana parents should also be aware that the income used for child support calculations considers tax obligations as an allowable deduction. This means that changes in tax rates, filing status, or available deductions can affect the child support calculation by changing the adjusted gross income figures used in the guidelines.

Special Considerations for Montana Child Support

Montana has several unique characteristics that can affect child support calculations and enforcement. Understanding these state-specific factors is important for parents navigating the child support system.

Self-Employment and Agricultural Income

Montana has a significant agricultural sector, and many parents derive income from farming, ranching, and related activities. Self-employment income from agricultural operations can be complex to calculate due to seasonal variations, commodity price fluctuations, and the distinction between business expenses and personal expenses. Montana courts are experienced in evaluating agricultural income and typically look at multiple years of tax returns and financial records to establish a reliable average income figure. The court may also consider the value of in-kind benefits such as housing provided by the farm or ranch operation.

Native American Tribal Jurisdiction

Montana is home to seven Indian reservations, and child support cases involving tribal members or children residing on reservations may involve tribal jurisdiction. Montana courts and tribal courts have concurrent jurisdiction in many child support matters, and the specific jurisdictional rules depend on the tribal affiliation of the parties, the location of the children, and applicable federal law including the Indian Child Welfare Act (ICWA). Parents involved in cross-jurisdictional cases should seek legal counsel familiar with both Montana state law and tribal law.

Military Families in Montana

Montana is home to Malmstrom Air Force Base and has a significant military and veteran population. Child support cases involving military members have special considerations including the calculation of military income (base pay plus allowances), federal protections under the Servicemembers Civil Relief Act (SCRA), and enforcement through the Defense Finance and Accounting Service (DFAS) for income withholding. Montana courts apply the standard guidelines but must account for the unique nature of military compensation and the practical challenges of service members' deployment and relocation schedules.

Frequently Asked Questions

Other State Child Support Calculators

Child support laws vary significantly from state to state. If you need to calculate child support for a different state, use one of our other state-specific calculators: