Itemize Montana 2024 taxes

Yes, the tax simplification bill that passed in 2021 and went into effect starting in tax year 2024 made several changes. One of the changes is how Montana calculates state taxable income. Prior to 2024, the calculation of Montana state taxable income started with Federal adjusted gross income (line 11 of Form 1040). This number was calculated before the federal standard or itemized deductions. 

However, now the Montana state taxable income calculation starts with Federal taxable income (line 15 of Form 1040). This number is calculated after the federal standard or itemized deductions.

Because of this change, if you take the federal standard deduction that's what will be used to calculate your state taxable income.

For more information, see the tax simplification resource hub.