2025 Montana State Tax Deadlines
Montana Individual income tax filing deadlines and extensions for 2025.
If you are a resident or have been involved in business operations within Montana, you might be required to file Montana State taxes. Montana maintains a progressive income tax system with rates ranging from 1% to 6.9%. Significant changes for 2025 include the transition to single-sales factor apportionment for Corporate income tax. This comprehensive guide outlines the key tax deadlines and considerations applicable to Montana in 2025.
Montana business tax deadlines for 2025
C Corporations' deadlines and requirements
C Corporations in Montana must file and pay Corporate Income Taxes by April 15, 2025.
Filing requirements include:
- Complete Montana Corporate Income Tax Return
- File online with the Montana Department of Revenue's e-filing system
- File by mail must be postmarked by the due date
- Payment must be made by April 15, 2025
Extension to file taxes in Montana for 2025
The Extension Deadline for Montana Corporate income tax returns is November 15, 2025. Montana automatically grants a six-month extension for filing Corporate income tax returns without requiring separate forms. This is an extension to FILE, not an extension to PAY—payment is still due April 15, 2025.
Pass-through entities
Montana S Corporations and Partnerships tax deadlines for 2025
S Corporations and Partnerships must file in Montana by March 15, 2025.
Required forms include:
- Montana S Corporation Tax Return
- Montana Partnership Tax Return
- Form PTE – Montana Pass-Through Entity Tax Return
Extension to file S Corporations and Partnerships taxes in Montana for 2025
The Extension Deadline for Montana S Corporations and Partnerships returns is September 15, 2025. Montana automatically grants six-month extensions on filing pass-through entity tax returns without requiring separate applications. This is an extension to FILE, not an extension to PAY—payment is still due March 15, 2025.
Montana Individual tax considerations for 2025
Filing requirements and income thresholds
Montana Individuals must file a State income tax return if they are Montana residents with income above certain thresholds or nonresidents with Montana-source income.
The 2025 filing thresholds are:
- Single taxpayers - $5,100
- Married filing jointly - $10,200
- Head of household - $7,650
- Married filing separately - $5,100
Estimated tax deadline for Montana 2025
Estimated tax payments are due:
- April 15, 2025
- June 15, 2025
- September 15, 2025
- January 15, 2026
Who must make estimated payments
You must make Montana estimated income tax payments during 2025 if you expect to owe $1,000 or more in state income tax after withholding and credits, and your withholding and estimated payments are less than 90% of the current year's tax or 100% of the prior year's tax.
Individual tax deadline for Montana 2025
You must file and pay Individual Income Taxes in Montana by April 15, 2025. Montana accepts electronic filing through the Montana Department of Revenue's e-filing system, which significantly saves time and processing efforts.
Available forms include:
- Form 2 – Montana Individual Income Tax Return
- Form 2NR – Montana Nonresident Individual Income Tax Return
Extension to file taxes in Montana for 2025
The Extension Deadline is October 15, 2025, to file your Montana Individual Income tax return. Montana automatically grants six-month extensions on filing personal income taxes without requiring separate extension forms. This is an extension to FILE, not an extension to PAY—payment is still due April 15, 2025.
What Montana tax professionals need to know
Several key considerations make Montana's tax landscape unique for 2025. Montana has a progressive income tax system with rates from 1% to 6.9%. The State implemented single-sales factor apportionment for Corporate income tax effective January 1, 2025, significantly changing how multistate corporations calculate their Montana tax liability.
Electronic filing requirements
Montana provides electronic filing options:
- Montana Department of Revenue's e-filing system
- Commercial tax software integration
- Professional tax preparation services with electronic submission
Single-sales factor apportionment implementation
Effective January 1, 2025, Montana's Corporate income tax apportionment formula changed from a three-factor formula to a single-sales factor apportionment, which may significantly impact the tax liability of multistate corporations in Montana.
Montana's unique tax features for 2025
No estate tax
Montana does not have a state estate tax, making it attractive for estate planning purposes compared to states that do impose such taxes.
Retirement income benefits
Montana provides favorable treatment for retirement income:
- Up to $4,800 in retirement income may be excluded for taxpayers under 65
- Taxpayers 65 and older may exclude up to $4,800 in pension and annuity income
- Social Security benefits receive favorable treatment
Agricultural and farming provisions
Montana offers special provisions for farmers and agricultural operations:
- If at least 2/3 of gross income is derived from farming, estimated tax may be paid by January 15, 2026
- Farmers who file their tax return by March 1, 2026, and pay the total tax at that time, need not file an estimated tax
- Various agricultural land use valuations and exemptions
Natural resource considerations
Montana's significant mining, oil, and gas industries face specific tax considerations, including severance taxes, depletion allowances, and various credits that can affect both business operations and Individual income for those employed in natural resource industries.
Sources
- Montana Department of Revenue
- Montana Individual Income Tax Information
- Montana Tax Forms and Information
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The material discussed on this page is meant for general illustration and/or informational purposes only and is not to be construed as investment, tax, or legal advice. You must exercise your own independent professional judgment, recognizing that advice should not be based on unreasonable factual or legal assumptions or unreasonably rely upon representations of the client or others. Further, any advice you provide in connection with tax return preparation must comply in full with the requirements of IRS Circular 230.
Please note that if any due date falls on a federal or state holiday or weekend, it may be adjusted to the next business day. Always verify current deadlines with the appropriate tax professional and authorities.
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