Montana Child Support & Parenting Time Calculations

Montana child support is based on parenting time percentages

Montana uses a parenting time percentage in its child support formula to determine the amount of child support in your divorce case.

Besides income, parenting time percentages are a key part of the Montana child support formula. Your parenting time directly affects your child support, whether you pay or receive.

Most parenting time totals are estimates (and thus incorrect)

Montana attorneys and judges often rely on parenting time estimates only, even if they are incorrect, because counting total hours is tedious and time consuming. Divorcing parents often rely on these estimates as well.

Using estimates means your parenting time totals are wrong when compared to your actual parenting time schedule. This means your child support amount will not be fair or exact.

How to calculate parenting time instead of relying on estimates

To calculate parenting time, the easiest and most accurate way is to use software. Without software, you're forced to count each night for a whole year, which is error-prone when you include alternating holidays, summer break, and any changes to the schedule throughout the year.

The leading parenting time calculation software, Custody X Change, can calculate your parenting time to see if it was estimated incorrectly.

Calculate Your Parenting Time Now

Using software, you can also tweak your schedule to see how even little changes affect your total parenting time, and you can see how your parenting time changes each year due to holidays and other events.

You can also track what actually happens, and show how much time you've actually received for any period of time. Historical information is a powerful tool when you request a child support modification or when you request more parenting time.

Fast facts on child custody and child support in Montana

In any divorce, Montana family courts award custody of the children to one or both parents. Custody is divided into legal custody and physical custody. The total parenting time factors into the child support formula for both sole and joint custody.

Montana sole physical custody: The children reside with and are supervised by the residential parent, while the other parent is entitled to scheduled visitations. In Montana, sole physical custody is given to the parent with whom the children spend the most time with.

Montana shared physical custody: Each parent has significant periods of physical custody, which allows them frequent and continuing contact with their children. Montana law outlines shared custody as any arrangement in which the child has regular and continuing contact with both parents. Shared physical custody is the most common form of custody awarded by family courts in Montana. Parenting time does not have to be equally divided to qualify for shared physical custody.

Montana child support formula and parenting time adjustment

Montana family courts use formulas that consider both parents' incomes and the needs of the child to arrive at a monthly child support amount.  A parenting time adjustment is given based on shared custody.

Sole custody formula: The total income between the two parents is put into the formula and then a basic monthly support is figured by using the Montana Child Support Guidelines. Certain deductions are allowed when figuring total income. To be considered a sole custody case, the non-residential parent spends fewer than 110 days per year, or less than 30 percent of the time, with the children. No parenting time credit is applied toward child support. The residential parent receives child support from the non-residential parents according to Montana law.

Joint custody formula: To qualify for joint custody, the Montana statues outline that the non-residential parent hosts the children for 110 days or more, up to 182, or 50 percent of the time.  The more time the non-residential parent spends with the children, the greater the child support reduction.

Examples of sole child custody and Montana child support

Consider the hypothetical case of Robert and Mary. After taking their gross annual incomes and then applying the standard deductions for things like health insurance for the children and a personal living allowance, a net annual child support obligation amount is set.

Robert has net annual child support obligation of $18,000 per year, while Mary's net annual child support is $9,000 per year. They have two children.

See how the child support amounts change in these examples:

  • Scenario #1: Robert is the non-residential parent in this sole custody case, and is scheduled to host the children for less than 110 days per year. He is not eligible for a parenting time credit. He pays $1,500 in child support each month to Mary.
  • Scenario #2: Mary is the non-residential parent and hosts the children for less than 110 days per year. She pays $750 in child support to Robert.

In Montana sole custody cases, the non-residential parent pays child support to the residential parent, regardless of income.

Examples of the shared custody formula in Montana child support

Robert has net annual child support obligation of $18,000 per year, while Mary's net annual child support is $9,000 per year. They have two children.

See how the child support amounts change in these examples:

  • Scenario #1: Robert hosts the children for 112 days or 31 percent, just over the minimum to qualify for shared physical custody. This qualifies him for a parenting time adjustment. He pays $1,469 child support per month to Mary.
  • Scenario #2: Robert hosts the children for 139 days, or 38 percent. He pays $1,050 in child support to Mary.
  • Scenario #3: Robert hosts the children for 164 days, or 45 percent. He pays $662 in child support to Mary.
  • Scenario #4: If Robert and Mary agreed to a 50/50 split, or 182 days, he pays $382 in child support. This is because he is the higher earner.
If Mary were the non-residential parent, she would pay child support to Robert, and be eligible for a parenting time adjustment based on the total number of overnights with the children.
Other factors in the Montana child support formula

Montana's child support formula uses the following information to calculate your monthly amounts for shared custody child support:

Eligible children: Any child under 18 or still in high school. Child support ends upon the 18th birthday or at graduation from high school, whichever is later, but no later than age 19.

Gross earnings: Gross earnings are established based on tax records and current pay stubs. Montana law requires the use of both parents' incomes from the equivalent of one full-time job to determine a child support amount.

Specific deductions: There are some deductions allowed by Montana family courts that allow an adjustment of the income, including a parental living allowance, health insurance premiums for the children, support for other children and child care expenses, for example.

How accurate child support helps your children

Paying accurate child support helps your children in several ways, primarily because it ensures their financial needs are met.

Here are some other reasons why accurate overnight numbers help you, the other parent and your children:

  • It provides a fair way to determine your child support amounts
  • It guarantees the child support amount reflects each parent's responsibilities
  • It allows for modifications if your actual time and scheduled time are different
  • It is compliant with Montana law

Your financial obligations to your children don't end with divorce, so whether you are paying or receiving child support, you owe it to your children to pay or receive the proper amount.

Top 5 things to remember about Montana child support and overnights

To ensure you are paying or receiving the right amount of child support in Montana, remember these 5 things:

  1. The child support amount is determined using guidelines established under state law in the M.C.A., Title 40, Ch. 5. The child support formula figures a base child support obligation based on the income from both parents.
  2. Montana family courts favor joint physical custody over sole physical custody.
  3. Sole physical custody means that the non-residential parent is scheduled for fewer than 110 days with the children per year. There is no parenting time credit given in sole custody cases.
  4. A parenting time credit is given in shared custody cases to non-residential parents who care for their children for 110 days or more. The higher the parenting time total, the lower the child support amount.
  5. The non-residential parent pays child support to the residential parent. In the case of an approximate 50/50 split in parenting time, the higher earner pays child support to the lower earner.

Use Custody X Change software to create a custody schedule that will quickly calculate the total parenting time for the Montana child support formula.

As you negotiate what kind of joint custody schedule will best fit your needs, the software will accurately calculate your parenting time percentage.


The leading parenting time calculation software, Custody X Change, can calculate your parenting time to see if it was estimated incorrectly.

Calculate Your Time

The leading parenting time calculation software, Custody X Change, can calculate your parenting time to see if it was estimated incorrectly.

Calculate Your Parenting Time Now