Montana capital gains tax calculator

Montana taxes capital gains on top of federal tax: long-term gains up to 4.1%; short-term up to 5.65% (ordinary rates).

Calculate my Montana tax

Your details

$
Income before capital gains. The 2026 standard deduction is subtracted automatically
$
Sale price minus your cost basis (what you originally paid)
Long-term gains up to 4.1%; short-term up to 5.65% (ordinary rates)
2026 IRS rates — Rev. Proc. 2025-32

Your tax estimate

Estimated total tax on the gain
$9,550
on a $50,000 long-term gain
Effective rate: 19.1%
81%you keep
Net gain (you keep)$40,450
Federal CGT$7,500
Montana tax$2,050
Capital gain$50,000
Federal long-term rate15.0%
Federal CGT$7,500
Total federal tax$7,500
Montana (4.1%)$2,050
Total tax$9,550
Net gain after tax$40,450
File with TurboTaxReporting a $50,000 gain? Let the software fill in Schedule D for youTurboTax handles capital gains, NIIT, Schedule D and Form 8949 automatically — including state returns. Import directly from your brokerage.Start with TurboTax →
Estimate only — 2026 IRS federal rates plus approximate state top marginal rates. Consult a tax professional before acting on these numbers.

What you would pay in Montana

Long-term gains (assets held more than a year) for a single filer with $75,000 of other income:

GainFederal + NIITMontanaTotal taxYou keep
$25,000$3,750$1,025$4,775 (19.1%)$20,225
$50,000$7,500$2,050$9,550 (19.1%)$40,450
$100,000$15,000$4,100$19,100 (19.1%)$80,900
$250,000$42,250$10,250$52,500 (21.0%)$197,500

Short-term vs long-term gains in Montana

Sell within a year and the federal government taxes the gain as ordinary income. On a $50,000 gain with the same income, that means $13,889 of tax if you sell short-term against $9,550 if you hold past one year, a difference of $4,339. Montana also treats the two differently: 5.7% on short-term gains and 4.1% on long-term gains.

How we estimate Montana tax

Long-term gains up to 4.1%; short-term up to 5.65% (ordinary rates). Where a state taxes gains as ordinary income on a sliding scale, the calculator applies the rate shown above to the whole gain, so for most people it is an upper estimate. Local and city income taxes are not included.

*Examples use 2026 IRS brackets, the standard deduction and the 3.8% Net Investment Income Tax. Change your filing status, income and holding period in the calculator above for your own figure.

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