How a Montana taxable value is actually built
Most of the energy spent arguing about property taxes goes into the three steps that cannot move. Knowing which step actually changed is the entire diagnosis.
The short version
Market value × a statutory rate = taxable value. Taxable value × mills ÷ 1,000 = the bill.
Five steps, and only the first two can ever be contested. Knowing which step moved is the whole diagnosis — it decides whether you file a form, file an appeal, or do nothing.
The five steps
Step 1 — The department sets a market value
MCA 15-8-111 requires property to be assessed at 100% of its market value. This is mass appraisal, not an individual walk-through: sales, cost and income models applied across a county. Two dates matter and neither is today. Values are set as of a valuation date that is already behind you when the notice arrives, and ownership and status are fixed at midnight on January 1 under MCA 15-8-201 — which is why a property sold in March is still billed to the January owner.
Contestable. This is one of the two real levers, and the evidence has to be tied to the valuation date rather than to what the place would fetch now.
Step 2 — It assigns a class
Montana has seventeen property classes. Residential and commercial both sit in class four but take different rates; agricultural land is valued on productive capacity, forest land on forest productivity. Parcels are prorated by use rather than classified all-or-nothing. What class four covers, and what escapes it.
Contestable — and this one has no deadline. A genuine classification error is correctable by the department under MCA 15-8-601 whenever it is found. You do not need an open appeal window, and it is often a phone call rather than a hearing.
Step 3 — A statutory rate turns value into taxable value
This is where HB 231 did its work. Residential with no claim on file takes a flat 1.9%; with a homestead or long-term rental claim it takes graduated bands starting at 0.76%. Commercial takes its own rate. The rate itself is set by the legislature.
Not contestable. A rate change is not an error and there is nothing to appeal. Where an election exists, the remedy is an application.
Step 4 — Every overlapping jurisdiction sets mills
A mill is one dollar of tax per thousand dollars of taxable value. Your total is the sum of county, city, school district and special district levies, and it varies street by street. This is why no tool — including ours — can turn an address into a dollar bill with a straight face.
Not contestable. Mills are set by elected bodies and by voters at the ballot box.
Step 5 — The treasurer multiplies and mails
Taxable value times mills divided by 1,000, plus any special assessments that are not value-based at all. Arithmetic — not contestable, though it is worth checking that the taxable value printed on the bill matches the notice you were sent.
Worked through, on a $450,000 house
With no claim on file, step 3 is one multiplication: $450,000 × 1.9% = $8,550 of taxable value.
With a homestead or long-term rental claim, the bands fill in order — cumulatively, never as a single lookup:
| Band | Market value in it | Rate | Taxable value |
|---|---|---|---|
| First band | $386,000 | 0.76% | $2,934 |
| Balance | $64,000 | 0.9% | $576 |
| Total | $450,000 | 0.78% | $3,510 |
Then step 5, using 650 mills purely as an illustration (your own number is on your bill, and it will differ):
| Taxable value | Tax at 650 mills | |
|---|---|---|
| No claim on file | $8,550 | $5,558 |
| Homestead or long-term rental claim | $3,510 | $2,282 |
| Difference | $5,040 | $3,276 |
Same house, same market value, same county. The only thing between those two rows is a form.
Reading a change correctly
When a taxable value moves, work out which step moved before deciding what to do. The arithmetic answers it:
| What you see | What moved | The response |
|---|---|---|
| Taxable value up ~2.5x, market value unchanged | Step 3 only | A claim form, if you have an election |
| Market value up, taxable value up in proportion | Step 1 | A value appeal, on a 30-day clock |
| Both moved | Steps 1 and 3 | Split them before choosing |
| The class is wrong for how the property is used | Step 2 | A correction request, no deadline |
Splitting a rate change from a value change is the single most useful thing you can do with a notice, and it takes one division: last year’s taxable value divided by last year’s market value gives the rate you were actually on. In 2025 that answer was 0.76% for residential property across the board — which is why so many 2026 increases are a rate story rather than a value story.
Why the mills do not simply float back down
There is a revenue cap — MCA 15-10-420 — that forces a jurisdiction to lower its mills when the taxable base grows. It is real, but subsection (5) exempts the school levies: the statewide equalization mills, the university levy, and every local school district levy. Those are fixed in mills, not in revenue, so a larger base simply collects more.
Since school levies are commonly the largest single line on a Montana bill, the float-down covers the minority of it. When your bill arrives, split the mill breakdown into capped (county, city) and uncapped (state, university, schools) before concluding anything about where the money went.
One consequence worth holding on to: because the median value and the band edges reset with every reappraisal, an individual bill can still rise sharply when a particular property gains value faster than its jurisdiction’s average. The cap holds total revenue roughly level, so an above-average increase shifts burden onto that parcel. That fact pattern is exactly what a value appeal is for.
Related
- The bands are cumulative, not a lookup
Montana's reduced-rate bands fill in order like tax brackets. Reading them as a lookup — finding your band and applying that rate to the whole house — overstates the taxable value on a larger home by thousands, and sends people into appeals with nothing to argue.
- Your taxable value went up. Here is what actually changed.
Montana taxable values jumped for 2026 and most of it is not an error. HB 231 made the reduced rates opt-in: the 0.76% rate that used to apply to everyone now requires an application. What changed, what you can still do, and what is not worth fighting.
- Can you still fix 2026?
The 2026 application window closed March 1 — but an owner who was eligible for the homestead rate and never applied can recover one year by informal appeal to the Department of Revenue, by May 31, 2027. There is no long-term-rental equivalent.
Where your own parcel stands
The rate check is free and takes about ten seconds — look up any Montana property and see which rate applies, which reduced rate it could qualify for, and the gap between them. No email required. If you would rather someone went through the whole notice, that is what we do.
Rates, deadlines and statutory citations verified against MCA Title 15 as of September 17, 2026. The median residential value ($386,000) and median commercial value ($379,000) are recalculated every two years with reappraisal — the next reset is in 2027. Up The Creek Research LLC is a public-records research firm, not a law firm, an accounting firm or an appraisal firm; this page explains what the statute provides and is not advice about your particular situation. See our Disclaimer & Terms.