Montana Online Child Support Calculator

Authored By: Montana Legal Services Association

Guide to the Montana Online Child Support Calculator (printable version available at the bottom of the page)

Make Sure the Calculator is Right for You

The calculator is not for everyone. You need to read all of the information below. If you do not read the following information, you may get an incorrect calculation or a calculation that you cannot use for your case.

The calculator is for people who need to calculate a child support amount they owe or are owed.


The calculator is for people who need the child support amount because they are filing one of the following types of court documents:

  • Petition for Dissolution with Children in a Montana District Court, or
  • Petition for Parenting Plan in a Montana District Court, or
  • Modification of Child Support Order in a previous Dissolution with Children or Parenting Plan case in a Montana District Court


More about the calculator:

  • The calculator is only for child support for children under age 18 or still in high school.
  • The calculator is for people who know both their own and the other parent’s incomes and financial situations.
  • The calculator will NOT calculate your taxes or calculate a medical support order.
  • The calculator does not currently calculate temporary income. If you have temporary income, please do not use the calculator as you may get an incorrect result.
  • The State of Montana Child Support Enforcement Division (CSED) can calculate child support in many situations. See
  • Some private attorneys can also calculate child support.
  • The calculator may not be right for you if you have a complicated case or situation. It cannot take the place of a lawyer’s legal advice or information from CSED. If you don’t know whether you should use the calculator, please talk to a lawyer or CSED before using it.


The Montana Legal Services Association (MLSA), the creators of the calculator, and CSED don’t claim or guarantee that using the calculator will help you get what you want. MLSA and/or CSED are not responsible for what happens if you use the calculator.



Please be careful with your personal information when using a computer. Make sure you log out and close all programs when you’re done and close all documents. Restart or shut down the computer when you are finished. Remember that even clearing a computer’s history does not totally erase your computer trail; someone might still be able to track the websites you visited and/or read the websites and documents you created.


If  someone is trying to keep track of what you do, it could be dangerous for you to use the calculator. For information on how to use computers safely, please contact the US National Domestic Violence Hotline at 1-800-799-7233 and TTY 1-800-787-3224.


Gather Information

It will be much easier for you to use the calculator if you gather information before you begin. Some of the information you will need is listed below. You will also need some of this information for the other parent:

·         Paystubs

·         Self-Employment income

·         Tax returns

·         Child daycare costs

·         Medical expenses for you and your children

·         Children’s unreimbursed medical expenses

·         Dependent benefits

·         Health insurance premiums

·         Long-distance parenting transportation costs

·         Employment names and dates

·         Unemployment income, workers’ compensation, Social Security benefits, retirement, interest/dividend income, reimbursements, grants, noncash benefits from employers

·         Tax deductions (Federal, state, FICA, Medicare, retirement, work costs)


Understand How to Use the Calculator

  • The calculator is hosted by the website. We strongly encourage you to create an account on the website. You can only save your answers and forms if you create and log into your account before you start answering questions.

  • The calculator will allow you to create Financial Affidavits and/or Child Support Worksheets
  • The link to the calculator can be found at the bottom of this page.
  • To use the calculator, you work your way through a set of questions and type in your answers. Once you have finished, the program will compile your answers and calculate child support. You can save your answers if you have created an account. You can also print or email your documents.


Know Where to Turn for More Information




  • The State of Montana Child Support Enforcement Division (CSED) can calculate child support in many situations. See
  • Montana Legal Services Association (MLSA) helps low-income people with civil legal problems. Apply online at or call the HelpLine at 1-800-666-6899 Monday-Thursday 8:30am-5:30pm and Fridays 8:30am-4:30pm.
  • The State of Montana Law Library can help with legal research and information. See call (800) 710-9827.
  • The Court Help Program can provide general information. See:


Help for Understanding the Questions

The calculator has many questions that include legal and technical words and terms. The “Help for the Montana Online Child Support Calculator” (also found at the bottom of the page) defines and explains many of the words and terms so that you better understand how to answer the questions.

Guide to the Montana Online Child Support Calculator - printable version

Help for the Montana Online Child Support Calculator - Printable PDF

Link to Montana Child Support Calculator:

Make the Calculator Better! Tell us about your experience:

Last Review and Update: Aug 26, 2016

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