Idaho diesel prices today
Idaho diesel prices todayDiesel averages $6.53 a gallon in Idaho on 2 October 2026 — the 12th most expensive of 51 states, and down $0.12 on the week.
Idaho against the other states
$0.17 a gallon above 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 Idaho is $4.97, so diesel costs $1.57 more per gallon — and more than premium at $5.56.
Tax on a gallon of diesel
$0.24 federal + $0.33 Idaho · 21st highest of 51. The rest — about $5.96 — 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 Idaho
AAA's diesel averages for 7 Idaho metro areas, cheapest first — $0.21 a gallon between the two ends.
| Metro area | Diesel | vs state |
|---|---|---|
| Coeur D'Alene | $6.40 | −$0.13 |
| Idaho Falls | $6.47 | −$0.06 |
| Pocatello | $6.50 | −$0.03 |
| Lewiston | $6.51 | −$0.03 |
| Boise City | $6.51 | −$0.02 |
| Franklin | $6.57 | +$0.03 |
| Twin Falls | $6.61 | +$0.07 |
Show the data as a table
What a diesel fill-up costs in Idaho
- Diesel car or SUV — 18 gal$117.61
- Heavy-duty pickup — 34 gal$222.16
- Box truck — 60 gal$392.04
- Semi truck, two tanks — 250 gal$1,633.50
Diesel in neighbouring states
More for Idaho
Frequently asked questions
How much is diesel in Idaho today?
$6.53 a gallon, AAA's Idaho average for 2 October 2026 — the 12th most expensive of 51 states. Regular gasoline is $4.97, so diesel costs $1.57 more per gallon.
Are diesel prices going up in Idaho?
Diesel is down $0.12 (1.8%) on a week ago, and up $2.72 on a year ago, when it was $3.82, on AAA's own earlier averages.
Where is diesel cheapest in Idaho?
Of the 7 metro areas AAA reports in Idaho, Coeur D'Alene has the cheapest diesel at $6.40 a gallon and Twin Falls the dearest at $6.61. Individual stations vary around these averages.
How much is the diesel tax in Idaho?
$0.57 a gallon: $0.24 federal plus $0.33 in Idaho state taxes and fees, the 21st highest of 51. The state average is $0.36. Rates as of 1 January 2026.
Is diesel cheaper in a neighbouring state?
Yes — Wyoming ($6.21, $0.32 less), Montana ($6.23, $0.30 less), Utah ($6.49, $0.04 less). On a 100-gallon fill that is up to $32.20; whether it is worth the drive depends on how far the border is.