How to Get an EIN Number in Montana: Online, Fax, or Mail

To get an EIN in Montana, apply directly with the IRS through the free online EIN Assistant at irs.gov. The application takes about ten minutes, and the IRS issues your nine-digit federal tax ID at the end of the session. The process is identical whether you’re forming an LLC, incorporating, or launching a nonprofit; only the details you enter about the entity change.1Internal Revenue Service. Get an Employer Identification Number

Do You Actually Need One

Not every Montana business owner needs an EIN. A sole proprietor with no employees and no excise tax obligations can use a Social Security Number for federal tax filings. But you’re required to get an EIN the moment any of the following is true:

  • You hire employees.
  • You operate as a corporation, partnership, or multi-member LLC. These entities need an EIN whether or not they have employees.
  • You have a Keogh or Solo 401(k) retirement plan.
  • You file for bankruptcy.
  • You buy or inherit an existing business.

Plenty of sole proprietors who don’t technically need one get an EIN anyway. It keeps your Social Security Number off invoices and W-9 forms, and most banks require one to open a business account. Montana’s Department of Revenue also requires a Federal Employer Identification Number to register a withholding tax account, so if you expect to hire anyone, having the EIN already saves a step.2Montana Department of Revenue. How to Open or Close a Montana Withholding Account

What to Have Ready Before You Apply

Gather everything before you start. The IRS online tool gives you 15 minutes of inactivity before the session expires, and you can’t save your progress.1Internal Revenue Service. Get an Employer Identification Number

Responsible party information. Every EIN application requires a “responsible party,” meaning the individual who controls or manages the entity. For a sole proprietorship, that’s you. For an LLC, it’s typically a managing member. For a corporation, it’s usually a principal officer. You’ll need this person’s name, Social Security Number (or ITIN), and address.

Legal business name. Enter it exactly as it appears on your Montana Secretary of State filing. Small differences in punctuation or abbreviations can cause processing delays.

Physical business address. The IRS requires a street address, not a P.O. Box, for the business location.3Internal Revenue Service. Instructions for Form SS-4 (12/2025)

Entity type. Know whether you’re applying as a sole proprietor, single-member LLC, multi-member LLC, corporation, partnership, or nonprofit. LLCs get a follow-up question because the IRS doesn’t recognize “LLC” as a tax classification; it treats your LLC as either a partnership, corporation, or disregarded entity depending on how many members you have and whether you’ve filed an election.3Internal Revenue Service. Instructions for Form SS-4 (12/2025)

Reason for applying. Common reasons include starting a new business, hiring employees, or banking purposes.

Start date and expected employee count. You’ll need the date the business started (or the date you acquired it) and an estimate of how many employees you expect in the next 12 months.

Nonprofits covered by a group exemption letter also need their four-digit Group Exemption Number.3Internal Revenue Service. Instructions for Form SS-4 (12/2025) One boundary worth noting: an EIN doesn’t make a nonprofit tax-exempt. For that, you file Form 1023, 1023-EZ, or 1024 separately.

The Three Ways to Apply

The IRS offers three application methods, all free. A fourth option, applying by phone, exists only for international applicants with no U.S. address.

Online (Fastest)

The IRS EIN Assistant at irs.gov is the fastest route. The tool walks you through the same questions as Form SS-4, and you receive your EIN the moment you finish. The system is available Monday through Friday, 7 a.m. to 10 p.m. Eastern Time. Two limitations to know: you can apply for only one EIN per responsible party per day, and the tool is not available to applicants whose principal place of business is outside the United States.1Internal Revenue Service. Get an Employer Identification Number

Fax

Download Form SS-4 from irs.gov, complete it, and fax it to 855-641-6935. If you include your fax number, the IRS will fax back your EIN in about four business days.4Internal Revenue Service. Employer Identification Number This is the best backup when the online tool is down or you’ve already used your one-per-day online application.

Mail

Send the completed Form SS-4 to:

Internal Revenue Service
Attn: EIN Operation
Cincinnati, OH 45999

Allow about four weeks for processing. The IRS notes that high inventory levels can cause additional delays.4Internal Revenue Service. Employer Identification Number Mail is realistically a last resort. Use it only if you can’t access the online tool or a fax machine and you have plenty of lead time.

Phone (International Applicants Only)

If you’re forming a Montana entity but have no legal residence or principal place of business in the United States, you can call 267-941-1099 (not toll-free), Monday through Friday, 6 a.m. to 11 p.m. Eastern Time. Have a completed Form SS-4 in front of you before calling. The IRS representative may ask you to fax or mail the signed form within 24 hours after the call.3Internal Revenue Service. Instructions for Form SS-4 (12/2025)

Skip the Paid Filing Sites

A lot of websites charge $50 to $300 to “file” your EIN application. They’re filling out the same free IRS form you can complete yourself in minutes. The Federal Trade Commission has warned consumers specifically about these sites, many of which use names and designs that imply an IRS affiliation they don’t have.5Federal Trade Commission. FTC Warns Operators of Websites that Charge for an Employer Identification Number and Claim Affiliation with the IRS The only legitimate site is irs.gov, and the tool is called the EIN Assistant. If you’re paying anyone for this, you’re paying for something the IRS provides for free.

After You Receive Your EIN

Online applicants can download or print the confirmation at the end of the session. Regardless of how you applied, the IRS mails an official notice called CP 575 to the address on your application. Store it somewhere safe. Banks, vendors, and state agencies routinely ask to see it.

Opening a Business Bank Account

Most banks will ask for your EIN along with your formation documents (Articles of Organization or Incorporation filed with the Montana Secretary of State), ownership agreements, a government-issued ID, and any applicable business licenses.6U.S. Small Business Administration. Open a Business Bank Account Having these ready prevents a second trip.

Registering With Montana State Agencies

Your federal EIN is the starting point for several Montana registrations:

  • Withholding tax account. If you have employees or issue W-2s or 1099s with Montana withholding, register a withholding account with the Montana Department of Revenue. You’ll need your FEIN to complete it.2Montana Department of Revenue. How to Open or Close a Montana Withholding Account
  • Business income tax. Any business with property, payroll, or sales in Montana must file an annual Montana business income tax return. The GenReg business registration form requires your FEIN.7Montana Department of Revenue. Business Registration Form GenReg
  • Unemployment insurance. Employers register separately with the Montana Department of Labor and Industry’s Unemployment Insurance Division.
  • TransAction Portal (TAP). Montana’s online tax system lets you file returns, make payments, and manage accounts. Setting up a business account on TAP involves identity verification through your SSN and prior Department of Revenue information.8Montana Department of Revenue. Register for the TransAction Portal (TAP)

When a Change Means a New EIN

An EIN stays with your business for life unless you change its legal structure. The general rule: if ownership or entity type changes, you need a new number. The common triggers:9Internal Revenue Service. When to Get a New EIN

  • Sole proprietors who incorporate, form a partnership, or declare bankruptcy.
  • Corporations that receive a new charter from the Secretary of State, convert to a partnership or sole proprietorship, or merge to create a new corporation.
  • Partnerships that incorporate, dissolve so one partner continues as a sole proprietor, or end one partnership and start a new one.
  • LLCs that terminate and form a new corporation or partnership.

Changes that don’t require a new EIN include moving your business address, changing your business name, or swapping the responsible party. For those updates, you file Form 8822-B (Change of Address or Responsible Party — Business) instead. If your responsible party changes, you must file Form 8822-B within 60 days.10Internal Revenue Service. Form 8822-B Change of Address or Responsible Party – Business It’s easy to forget because nothing prompts you. A co-founder leaves, a new manager takes over, and no one tells the IRS.

If You Lose Your EIN

Can’t find your CP 575 notice and don’t remember your EIN? Try these in order:4Internal Revenue Service. Employer Identification Number

  • Check your bank. The institution where you opened your business account has your EIN on file.
  • Check state or local agencies. If you’ve applied for a Montana business license or registered with the Department of Revenue, those records include your EIN.
  • Call the IRS Business and Specialty Tax Line at 800-829-4933, Monday through Friday, 7 a.m. to 7 p.m. your local time. After verifying your identity, an agent will provide the number over the phone.11Internal Revenue Service. Telephone Assistance Contacts for Business Customers
  • Request Letter 147C, an IRS-issued letter confirming your previously assigned EIN. Request it through the same phone number or by requesting an Entity transcript online.