MT
Montana Small Business Tax Guide
What Montana's Department of Revenue says about sales tax, corporate income tax and estimated payments, with the date each page was checked. Background reading, not tax advice.
Disclaimer: This page is educational content only. Tax laws change, and your situation may differ. It is not legal, tax, or financial advice. Consult a qualified professional licensed in Montana before making filing or planning decisions.
Tax landscape for small businesses
Montana's Department of Revenue (DOR) administers the state's income taxes, and the Montana Code Annotated sets the rates. This page quotes both, plus the IRS for federal points. Montana's individual income tax brackets aren't quoted here; check the DOR's tax tables for your year.
On sales tax, the DOR (Montana, checked October 31, 2026) says: "Montana does not have a general-use sales tax." Selling into other states is a separate matter; the same page says: "Montana businesses selling online products to buyers in a state, such as South Dakota, that requires online retailers to collect sales tax will need to collect and pay those sales taxes."
For corporations, the DOR's corporate income tax page (Montana, checked October 31, 2026) lists a "Standard Rate" of "6.75%", and the Montana Code Annotated 2025, section 15-31-121 (Montana, checked October 31, 2026), says: "Each corporation subject to taxation under this part shall pay a minimum tax of not less than $50."
A worked example with sample figures, using the 6.75% standard rate the DOR quotes (Montana, checked October 31, 2026): a corporation with $40,000.00 of Montana net income owes $40,000.00 × 6.75% = $2,700.00, which is above the quoted $50 minimum. An invoice from a Montana business to a Montana customer has no state general sales tax line to add.
Tax overview
Each row lists a tax area and its notes. Confirm current figures with your state's tax agency or the IRS.
| Tax type | Rate or basis | Notes |
|---|---|---|
| General sales tax (DOR) | "does not have a general-use sales tax" | Montana, checked October 31, 2026. |
| Corporate income tax (DOR) | "6.75%" standard rate | Montana, checked October 31, 2026. MCA 15-31-121 sets a "minimum tax of not less than $50". |
| Corporate estimated tax (DOR) | If owing "$5,000 or more" | Montana, checked October 31, 2026: quarterly estimated payments then apply. |
| Self-employment tax (federal) | "15.3%" | An IRS rate for the whole of the US (federal); IRS page last reviewed or updated October 30, 2026. |
Filing requirements
This list isn't a complete checklist for your business.
Corporate return due date
The DOR's corporate income tax page (Montana, checked October 31, 2026) gives "May 15" as the filing due date for a "Calendar Year" return. It says "Extension Deadlines are for Returns Only" and "Any tax liability must still be paid by the original due date or it will be subject to uniform penalties and interest."
Corporate estimated payments
The same page (Montana, checked October 31, 2026) says: "If your business estimates owing $5,000 or more, you will need to make quarterly estimated tax payments." and "Estimated payments are due on the 15th of the fourth, sixth, ninth, and twelfth months of your tax year."
Individual estimated payments
The DOR's estimated payments page (Montana, checked October 31, 2026) says: "If you estimate you will owe more than $500 in tax for last year, you should make quarterly estimated payments this year." For calendar-year filers it lists "First payment: April 15", "Second payment: June 15", "Third payment: September 15" and "Fourth payment: January 15 (of the following year)".
Federal estimated tax
In the US (federal), the IRS estimated taxes page (last reviewed or updated September 25, 2026) says: "Individuals, including sole proprietors, partners, and S corporation shareholders, generally have to make estimated tax payments if they expect to owe tax of $1,000 or more when their return is filed."
Deductions and write-offs
Confirm with your state how it treats each item.
- SE tax adjustment: in the US (federal), the IRS self-employment tax page (last reviewed or updated October 30, 2026) says "you can deduct the employer-equivalent portion of your SE tax when calculating your adjusted gross income."
- Health insurance: the same IRS page says "a deduction, for income tax purposes, is allowed to self-employed individuals for the cost of health insurance."
- This page doesn't list Montana deductions or credits; for those, contact the DOR or a tax professional.
Practical tips
- Selling to customers in other states? The DOR (Montana, checked October 31, 2026) says online sellers into states such as South Dakota "will need to collect and pay those sales taxes."
- Buying goods to resell from an out-of-state vendor: the DOR (Montana, checked October 31, 2026) says "If you are a Montana business and need to send a resale certificate to your vendor, you may use the Montana Business Registry Resale Certificate." It adds that the vendor "may accept this certificate as a substitute “resale certificate” and exempt the transaction from the state's sales, use, or transaction tax, but they are not required to accept it," and that "Montana does not have a sales tax exemption certificate."
- Billed's invoice software page says: "Save your tax rates and settings once, and Billed calculates taxes automatically when you create invoices and estimates."
- Pay corporate tax by the original due date even when you extend the return; the DOR (Montana, checked October 31, 2026) says "Extension Deadlines are for Returns Only".
- Billed's financial reporting page says: "All reports in Billed can be exported for use with your accountant, bookkeeper, or tax software."
Frequently asked questions
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At a glance
| Topic | Montana source |
|---|---|
| Sales tax | DOR, Sales Tax Guidance |
| Corporate rate and due dates | DOR, Corporate Income Tax |
| Corporate minimum tax | Montana Code Annotated, 15-31-121 |
| Estimated payments | DOR, Making Estimated Tax Payments |
When this isn't for you
Lodging facility and other special Montana taxes, payroll withholding and individual income tax brackets fall outside this page. For them, or for advice on your own taxes, go to the Montana DOR or a tax professional.