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Montana Mortgage Calculator

The median Montana homeowner pays about $2,535 a year in property tax — roughly $211 a month on top of principal, interest and insurance — against a median home value near $338,100. That is an effective rate of about 0.75%, the 30th highest of the 50 states, where the 50-state average is near 0.99%.

Written and maintained by Chetan Mane · Methodology and sources · Data last reviewed September 2026

How to use this calculator

  • - Select Montana in the state field to apply the 0.75% average property tax rate.
  • - Adjust the price toward the Montana median of $338,100 to see what a typical local purchase costs each month.
  • - Remember the estimate uses the statewide average — Gallatin County and the rest of the state can differ noticeably.

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Property taxes use your state’s average rate.

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Principal and interest, property tax, insurance, mortgage insurance and HOA — itemised.

What actually sets Montana apart

Montana has no general sales tax, so schools and local government lean on property tax more heavily than in neighbouring states. Combined with a reappraisal cycle that captures market moves in steps, that produces occasional large jumps for owners in fast-appreciating western valleys.

Property taxes in Montana at a glance

  • Average effective tax rate: 0.75% of home value per year
  • Median home value: $338,100
  • Estimated tax on a median-value home: $2,535 per year (about $211 per month)
  • Rank by tax rate: 30th of 50, highest first
  • Rank by amount actually paid: 27th of 50, highest first
  • Where these figures come from: U.S. Census Bureau, American Community Survey 5-year estimates, for the Montana statewide averages shown above — ACS 2019-2023 5-year estimates, last reviewed September 2026.

Rate and bill agree in Montana

Montana sits 30th of the fifty by tax rate and 27th by the amount a median-value owner actually pays. That agreement is less common than it sounds: 19 of the 50 states move ten places or more between the two rankings, because home values vary far more widely than rates do. In Montana the 0.75% headline is a fair summary rather than a figure that needs correcting.

How Montana works out what you owe

The Department of Revenue appraises residential property on a statewide cycle and applies a statutory tax rate percentage to arrive at taxable value, which local mills are then applied to.

Montana sets no statutory limit on how fast a home's taxable value can rise, so a Montana assessment tracks the market more closely than it would in a capped state.

Exemptions Montana homeowners should claim

Each of these reduces a Montana bill every year you hold the property, and almost none are granted without a claim:

  • Property Tax Assistance Program: Reduces the tax rate applied to a primary residence for lower-income owners, on a sliding scale.
  • Elderly Homeowner and Renter Credit: A refundable income tax credit for residents aged 62 or older, based on the property tax paid relative to income.

Where you buy inside Montana changes the bill

A statewide average hides its extremes. Where they show up in Montana:

  • Gallatin County: Bozeman, where appreciation has been the sharpest in the state and reappraisal produced the largest increases
  • Yellowstone County: Billings, the largest population centre and a more stable market
  • Missoula County: high combined mills relative to the rest of the state, with a large university-driven rental sector

Montana and its neighbours

The same $338,100 — the Montana median — taxed at each neighbouring state's average rate:

  • North Dakota at 0.99%: about $3,347 a year, roughly $812 more than the $2,535 a Montana owner would pay on the same value.
  • South Dakota at 1.09%: about $3,685 a year, roughly $1,150 more than the $2,535 a Montana owner would pay on the same value.
  • Wyoming at 0.58%: about $1,961 a year, roughly $574 less than the $2,535 a Montana owner would pay on the same value.
  • Idaho at 0.53%: about $1,792 a year, roughly $743 less than the $2,535 a Montana owner would pay on the same value.

Appealing a Montana assessment

If the assessed value on your Montana home overstates what it is worth, the route is an appeal to the county Tax Appeal Board, then the Montana Tax Appeal Board. The window is within 30 days of the classification and appraisal notice, and it is strict — missing it means waiting a full cycle.

Frequently asked questions

When are Montana property taxes due, and when must exemption claims be filed?

Bills are issued in the autumn, with instalments due 30 November and 31 May. Assistance programmes are applied for with the Department of Revenue, generally by 1 April; the elderly credit is claimed with the state return.

Does this calculator use my exact Montana county tax rate?

No — it applies the Montana statewide average of 0.75%. Rates are set locally, and the spread inside Montana is wide enough to matter: on a $338,100 home, $797 a year separates Montana from an averagely taxed state before any county variation is counted. Check the parcel's own rate with its Montana county before relying on this figure.

Reference sources

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How this estimate is built

Principal and interest come from the standard amortization formula, worked through in full on the formula reference page. Property tax, insurance, PMI and loan-program figures layer on top from published assumptions — each one sourced, dated and listed on the methodology page. Every result here is an estimate built from public data, not a quote: confirm the specifics with a lender before relying on it.

For developers

This calculation is also available as a REST API and through an MCP server, both running the same engine as this page — so the figures match by construction rather than by convention. No key required.