Rocky Mountain region
IdahoGas prices
EIA doesn’t publish a weekly price for Idaho on its own. This figure starts from the Rocky Mountain average of $4.417 for the week of October 5, 2026 and adjusts it for Idaho’s fuel tax, which is 1.1¢ a gallon above the regional norm. How we estimate it.
Rocky Mountain prices this week
The regional averages Idaho’s figures are drawn from, in dollars per gallon.
- Regular
- $4.417
- Down $0.069 on the week
- Midgrade
- $4.749
- Down $0.061 on the week
- Premium
- $5.097
- Down $0.079 on the week
- Diesel
- $6.267
- Down $0.140 on the week
The regional price is near its most expensive point of the past year: over the past 52 weeks it has run from $2.403 to $4.587, averaging $3.541. It has moved +2.4% over four weeks and +20.7% over thirteen.
How much of a gallon is tax
Idaho charges 33.0¢ a gallon in state tax, the 20th highest of 51 (the 50 states and D.C.). With the federal tax that is 51.4¢, about 12% of the pump price.
| State excise tax | 32.00¢ |
|---|---|
| Other state taxes and fees | 1.00¢ |
| Federal excise tax | 18.40¢ |
| Total per gallon | 51.40¢ |
| On a 15-gallon fill | $7.71 |
| Over a year of typical driving | $247 |
From EIA’s notes for Idaho: Petroleum Transfer Fee (all fuels): $0.0100/gal.
Source: EIA federal and state motor fuel taxes, July 2026. A typical year assumes 480 gallons (about 12,000 miles at 25 mpg). Local sales taxes are not included.
Fuel tax in Idaho and its neighbours
Across the line in Nevada, state tax is 9.2¢ a gallon lower, which is $1.38 less tax on a 15-gallon fill.
| State | State tax | Versus ID | On a 15-gal tank |
|---|---|---|---|
| Nevada | 23.8¢ | −9.2¢ | −$1.38 |
| Wyoming | 24.0¢ | −9.0¢ | −$1.35 |
| Idaho | 33.0¢ | — | — |
| Montana | 33.8¢ | +0.8¢ | +$0.11 |
| Utah | 38.5¢ | +5.5¢ | +$0.83 |
| Oregon | 40.0¢ | +7.0¢ | +$1.05 |
| Washington | 60.2¢ | +27.2¢ | +$4.08 |
What driving in Idaho costs
- A 15-gallon fill
- $66.42
- A year of typical driving
- $2,125
- Versus the national average
- $36 a year more
Planning a drive? The fuel cost calculator prices a trip at this week’s Idaho figure, for your own car.
How we estimate the Idaho price
The U.S. Energy Information Administration surveys retail gasoline prices every Monday, but it reports individual figures for only nine states. Idaho is counted in the Rocky Mountain series, which averages it together with Colorado, Montana, Utah and Wyoming.
Within one region, crude oil, refining and most delivery costs are shared. The biggest fixed difference from one state to the next is tax, which reaches the pump almost cent for cent. So we take the regional average and add the gap between Idaho’s tax (33.0¢) and the average tax across the region’s states (31.9¢).
Local taxes, how busy the local market is and how far the state is from a refinery all move real prices too, so treat this as a guide to within a few cents, not a quote. Our methodology covers how every figure on the site is sourced.
Gas prices in Idaho
- How much is gas in Idaho right now?
- Regular gasoline in Idaho is estimated at about $4.43 a gallon this week. That starts from the EIA's Rocky Mountain average of $4.417 and adjusts it for Idaho's fuel tax, which is 1.1¢ a gallon above the average across the region's states. The national average is $4.354.
- How much is the gas tax in Idaho?
- Idaho charges 32.00¢ a gallon in state excise tax plus 1.00¢ in other per-gallon taxes and fees, 33.00¢ in all. That ranks 20 of 51 (the 50 states and D.C.), highest first. With the 18.4¢ federal tax, a gallon carries 51.4¢ of tax.
- Is gas cheaper in a state next to Idaho?
- On tax alone, yes. Nevada has the lowest fuel tax of Idaho's neighbours at 23.8¢ a gallon, 9.2¢ less than Idaho. On a 15-gallon fill that is $1.38 less tax. Station prices vary, so the saving at any one pump can be larger or smaller.
- Why is there no official weekly gas price for Idaho?
- The EIA's weekly survey samples about 1,000 stations nationwide, enough for reliable regional averages and for nine large states, but not for every state on its own. Idaho is counted in the Rocky Mountain series, which is updated every Monday and published on Tuesday.