Montana diesel prices today
Montana diesel prices todayDiesel averages $6.23 a gallon in Montana on 2 October 2026 — the 30th most expensive of 51 states, and down $0.08 on the week.
Montana against the other states
$0.13 a gallon below the unweighted mean of AAA's 51 state averages ($6.36). The cheapest diesel is in Texas at $5.79, the dearest in California at $8.38.
Regular gas in Montana is $4.53, so diesel costs $1.70 more per gallon — and more than premium at $5.24.
Tax on a gallon of diesel
$0.24 federal + $0.30 Montana · 31st highest of 51. The rest — about $5.69 — is the fuel itself, refining, distribution and the retailer’s margin.
Rates as of 1 January 2026. Local taxes, where they apply, are not included.
Diesel prices by city in Montana
AAA's diesel averages for 3 Montana metro areas, cheapest first — $0.08 a gallon between the two ends.
| Metro area | Diesel | vs state |
|---|---|---|
| Billings | $6.16 | −$0.07 |
| Great Falls | $6.18 | −$0.05 |
| Missoula | $6.23 | +$0.00 |
Show the data as a table
What a diesel fill-up costs in Montana
- Diesel car or SUV — 18 gal$112.12
- Heavy-duty pickup — 34 gal$211.79
- Box truck — 60 gal$373.74
- Semi truck, two tanks — 250 gal$1,557.25
Diesel in neighbouring states
More for Montana
Frequently asked questions
How much is diesel in Montana today?
$6.23 a gallon, AAA's Montana average for 2 October 2026 — the 30th most expensive of 51 states. Regular gasoline is $4.53, so diesel costs $1.70 more per gallon.
Are diesel prices going up in Montana?
Diesel is down $0.08 (1.2%) on a week ago, and up $2.63 on a year ago, when it was $3.60, on AAA's own earlier averages.
Where is diesel cheapest in Montana?
Of the 3 metro areas AAA reports in Montana, Billings has the cheapest diesel at $6.16 a gallon and Missoula the dearest at $6.23. Individual stations vary around these averages.
How much is the diesel tax in Montana?
$0.54 a gallon: $0.24 federal plus $0.30 in Montana state taxes and fees, the 31st highest of 51. The state average is $0.36. Rates as of 1 January 2026.
Is diesel cheaper in a neighbouring state?
Yes — South Dakota ($6.03, $0.20 less), North Dakota ($6.09, $0.14 less), Wyoming ($6.21, $0.02 less). On a 100-gallon fill that is up to $20.10; whether it is worth the drive depends on how far the border is.