Due Dates
- Returns
- April 15
- Extension
- October 15
Tax Types
Individual Income TaxBefore you file your Montana individual income tax return, be sure to have any documents, records, or forms you’ll need.
The documents listed on this page are not a comprehensive list.
Your situation will determine which forms you need. A qualified tax professional can help you determine your specific needs.
Keeping Tax Records
Keep your tax records organized and available. You will need to provide them to us if we request them during an audit.
Your tax records should include:
- A copy of your return
- Any credit claim forms
- Income statements
- Wage statements (Form W-2)
- Forms 1099
- Financial statements
- Bank statements
- Contracts
- Other income documents
- Deduction and expense statements
- Canceled checks
- Bank statements
- Paid invoices
- Sales receipts
- Mortgage interest (Form 1098)
- Loan documents
- Financial and legal documents
- Mileage logs
- Appointment Books
- Credit card statements
- Other expense or claims documents
You should keep tax records at least until the statute of limitations expires for that return.
In Montana, this is usually three years from the due date of the return or the day it was filed, whichever is later.
If you under-report your income by 25% or more, the statute of limitations increases to six years.
There is no statute of limitation for audits of false or fraudulent returns.
There are times when you may wish to keep your records longer than the normal statute of limitations. Two examples include property records and net operating losses.
A qualified tax professional can help you determine other records you may need to keep.
You should keep property records for:
- as long as you own the property.
- as long as you they are needed to figure original or replacement value.
- at least five years after you report the sale or disposition of the property on your return.
Net Operating Loss may be carried forward up to 20 years and any return claiming the net operating loss may be subject to an audit.
You should keep net operating loss records for all years you claim the loss for at least five years after the last year you claimed the loss.
