How to Modify Child Support in Montana
Reviewed by DocDraft Legal Team · Montana · Last updated September 21, 2026
In Montana, a child support modification is a court or agency order that changes the amount of an existing child support order after circumstances change, and Montana sets an unusually high bar in district court: you must show changed circumstances so substantial and continuing as to make the current terms unconscionable (MCA 40-4-208). Child support in Montana follows the state's administrative child support guidelines tied to each parent's income and time with the child (ARM 37.62), so a lasting income change, a job loss, or a new parenting schedule can make the current amount too high or too low. You can seek a change in two ways. You can file a motion to modify with the district court that issued your order, or, if the Child Support Services Division (CSSD) manages your case, you can ask that agency for a review. CSSD generally reviews an order when 36 months have passed, or sooner when one or both parents' income has changed by at least 30 percent. A change applies only to installments that come due after the other parent gets actual notice of your motion, so support that already came due cannot be reduced (MCA 40-4-208). Keep paying your current order until it is changed. Attorney review of your filing is available through DocDraft.
Find out where you stand in Montana
Where are you with changing your child support order?
DocDraft provides document preparation, not legal advice.
How do I modify child support in Montana?
File a motion to modify with the district court that issued your order, or ask the Child Support Services Division (CSSD) to review it if that agency manages your case. For a court change, you must show changed circumstances so substantial and continuing that the current terms are unconscionable (MCA 40-4-208).
How much does income have to change to modify child support in Montana?
Montana's district courts set no fixed percentage; you must show changed circumstances so substantial and continuing as to make the terms unconscionable (MCA 40-4-208). The Child Support Services Division generally reviews an order when one or both parents' income has changed by at least 30 percent, or after 36 months.
How far back can a child support change go in Montana?
A modification reaches only installments that come due after the other parent receives actual notice of your motion to modify, not back to when your circumstances changed (MCA 40-4-208). Support that already came due cannot be reduced, so filing promptly protects you. Keep paying the current order until it is changed.
Which court handles child support modifications in Montana?
The district court in the county where your existing order was issued handles modifications. If the Child Support Services Division manages your case, you can instead ask that agency to review and adjust the order administratively without a full court hearing. Both paths apply the Montana child support guidelines.
Montana child support modification at a glance
In Montana, a child support modification is a district court or CSSD order that changes an existing child support order after circumstances change, and the court standard is strict: you must show changed circumstances so substantial and continuing as to make the current terms unconscionable (MCA 40-4-208). Support follows the state's administrative guidelines tied to income and parenting time (ARM 37.62), so a lasting income change or a new schedule can justify a new amount. You file a motion to modify with the district court, or ask the Child Support Services Division to review your order; CSSD generally acts after 36 months, or sooner when a parent's income has changed by at least 30 percent. A change applies only to installments that come due after the other parent gets actual notice of your motion, so support already due cannot be reduced (MCA 40-4-208).
Lowering a Montana order after a lasting pay cut
Suppose your Montana order was set two years ago and your hours were just cut for good. Because a district court will change support only on changed circumstances so substantial and continuing as to make the terms unconscionable (MCA 40-4-208), you prepare a motion to modify with a financial affidavit showing your lower income and file it with the district court that issued your order. You serve the other parent right away, because a change reaches only installments coming due after they receive actual notice of your motion (MCA 40-4-208), and you keep paying the current amount until the judge rules. At the hearing the judge recalculates support under Montana's guidelines (ARM 37.62) and signs a lower order effective from the date of notice. Attorney review of your filing is available through DocDraft.
Relevant Laws
MCA 40-4-208 (modification standard and retroactivity)
Provides that a decree may be modified as to support only as to installments accruing subsequent to actual notice to the parties of the motion for modification, and that a support modification requires a showing of changed circumstances so substantial and continuing as to make the terms unconscionable.
ARM 37.62.2103 (availability of a CSSD review)
Sets when the Child Support Services Division may review an order, including after 36 months or, before then, upon a significant change such as an increase or decrease of at least 30 percent in a parent's income under the Montana child support guidelines.
Montana Child Support Services Division: modify an order
The Montana DPHHS CSSD page explains its administrative review process, stating a review is available when it has been at least 36 months since the order was entered or last reviewed, or when a parent's income has changed by at least 30 percent, using a Request for Review packet.
Montana Judicial Branch court forms
The Montana Judicial Branch forms index links to family law and child support materials for self-represented parties; Montana has no single statewide child support modification form, so a motion to modify uses the district court's family law packet.
Regional Variances
Montana child support modification rules at a glance
Qualifying threshold
Montana district courts require changed circumstances so substantial and continuing as to make the current terms unconscionable, with no fixed percentage (MCA 40-4-208). CSSD generally reviews when a parent's income has changed by at least 30 percent, or after 36 months.
Where to file
The district court in the county that issued your order, through its family law process. If the Child Support Services Division manages your case, you can instead ask that agency to review and adjust the order administratively.
Modification form
Montana has no single statewide court form to modify child support; you file a motion to modify using your district court's family law packet. A CSSD review starts with a Request for Review packet from the agency.
Retroactivity
A change applies only to installments coming due after the other parent receives actual notice of your motion to modify (MCA 40-4-208). Support that already came due cannot be reduced.
Periodic review
If CSSD handles your case, you can generally request a review about every 36 months without showing a change, and sooner when a parent's income changes by at least 30 percent.
Suggested Compliance Checklist
Gather proof of your changed circumstances
Before you file days after startingCollect current pay stubs, tax returns, and proof of the change (job loss, income change, or a new parenting schedule), and estimate the new amount under Montana's guidelines (ARM 37.62). Attorney review of your filing is available through DocDraft.
Prepare your motion to modify
As soon as your circumstances change days after startingDraft a motion to modify child support for the district court that issued your order, with a financial affidavit and income proof. Montana has no statewide modification form, so use your local court's family law packet.
File with the district court
Promptly (the change dates back only to notice) days after startingFile your motion with the district court clerk and pay the fee, or ask the court to waive it. Because a change reaches only installments due after notice, file and serve promptly (MCA 40-4-208).
Give the other parent notice
Right after filing days after startingServe the other parent with your filed motion under Montana's service rules, then file proof of service. A modification reaches only installments coming due after the other parent receives actual notice of your motion.
Consider a CSSD review
Anytime your case is with the agency days after startingIf the Child Support Services Division manages your case, request a Request for Review packet. Review is generally available after 36 months, or sooner when a parent's income has changed by at least 30 percent.
Attend the hearing and get the new order
On your hearing date days after startingGo to the hearing with your income proof, let the judge recalculate support under Montana's guidelines, and get the signed order effective from the date of notice. Keep paying the current order until then.
| Task | Description | Document | Days after starting |
|---|---|---|---|
| Gather proof of your changed circumstances | Collect current pay stubs, tax returns, and proof of the change (job loss, income change, or a new parenting schedule), and estimate the new amount under Montana's guidelines (ARM 37.62). Attorney review of your filing is available through DocDraft. | - | Before you file |
| Prepare your motion to modify | Draft a motion to modify child support for the district court that issued your order, with a financial affidavit and income proof. Montana has no statewide modification form, so use your local court's family law packet. | - | As soon as your circumstances change |
| File with the district court | File your motion with the district court clerk and pay the fee, or ask the court to waive it. Because a change reaches only installments due after notice, file and serve promptly (MCA 40-4-208). | - | Promptly (the change dates back only to notice) |
| Give the other parent notice | Serve the other parent with your filed motion under Montana's service rules, then file proof of service. A modification reaches only installments coming due after the other parent receives actual notice of your motion. | - | Right after filing |
| Consider a CSSD review | If the Child Support Services Division manages your case, request a Request for Review packet. Review is generally available after 36 months, or sooner when a parent's income has changed by at least 30 percent. | - | Anytime your case is with the agency |
| Attend the hearing and get the new order | Go to the hearing with your income proof, let the judge recalculate support under Montana's guidelines, and get the signed order effective from the date of notice. Keep paying the current order until then. | - | On your hearing date |
Frequently Asked Questions
A real, lasting income drop can support a modification, but you must file a motion to modify or ask CSSD to review; support keeps accruing at the old rate until an order changes it (MCA 40-4-208). A court may weigh whether you are earning what you reasonably could. Do not simply stop paying.
No. Either parent can file a motion to modify in district court on their own, and the other parent is served and can respond. If both parents agree on a new amount, they can submit a written stipulation for a judge to approve, which is still measured against the Montana guidelines (ARM 37.62).
After you file in district court, the court sets a hearing, often several weeks to a few months out depending on the county. A CSSD administrative review can take up to about 180 days. Because a change reaches only installments due after notice, filing and serving promptly protects you (MCA 40-4-208).
Yes. If CSSD manages your case, you can ask it to review your order. A review is generally available after 36 months, or sooner when one or both parents' income has changed by at least 30 percent. If a change is warranted, CSSD can issue a new administrative order.
You can ask whenever a substantial and continuing change occurs. If CSSD handles your case, you can generally request a review about every 36 months even without showing a change, under federal rules, and sooner when a parent's income shifts by at least 30 percent.
A modification reaches only installments coming due after the other parent receives actual notice of your motion (MCA 40-4-208). Support that already came due, called arrears, cannot be reduced or erased by a modification. Keep paying your current order to avoid building arrears while your request is pending.
Montana has no single statewide court form to modify child support, so you file a motion to modify with the district court that issued your order, using your local court's family law packet and a financial affidavit. For a CSSD review, you request a Request for Review packet from the agency.
Filing a motion to modify in district court carries the standard filing fee, but you can ask the court to waive it if you cannot afford it. Asking the Child Support Services Division to review your order does not charge you a fee. Fee amounts vary by county.
Other Montana guides
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