Idaho vs Wyoming gas prices
Regular gas is $0.17 a gallon cheaper in Wyoming — $2.60 on a 15-gallon fill-up. The two share a border, so that gap is worth knowing before you cross it.
Idaho
Wyoming| Grade | ID | WY | Diff. | |
|---|---|---|---|---|
| Regular | $4.31 | $4.14 | $0.17WY | Wyoming |
| Midgrade | $4.60 | $4.45 | $0.14WY | Wyoming |
| Premium | $4.87 | $4.71 | $0.16WY | Wyoming |
| Diesel | $5.32 | $5.10 | $0.21WY | Wyoming |
Where the $0.17 gap actually comes from
52% of it is tax. Idaho charges $0.09 more per gallon in federal and state taxes than Wyoming. The remaining $0.08 is a real difference in what the fuel, refining and distribution cost — refinery proximity, pipeline access and state fuel-blend rules.
Fuel, refining, distribution and marginFederal and state taxes Pre-tax figures are estimates — see the note below.
What the gap is worth
Based on today’s $0.17 per-gallon difference, which moves week to week. Use the fuel cost calculator for your own mileage and vehicle.
Prices by metro area
State averages hide a lot. These are the cheapest metros AAA reports on each side.
Other comparisons
Frequently asked questions
Is gas cheaper in Idaho or Wyoming?
Regular gas is cheaper in Wyoming, at $4.14 a gallon against $4.31 in Idaho — a gap of $0.17, or 4.2%. On a 15-gallon fill-up that is $2.60. Figures are AAA daily state averages for 2026-08-02.
Why is gas more expensive in Idaho?
52% of the $0.17 gap is tax rather than the cost of the fuel. Idaho levies $0.09 more per gallon in federal and state taxes; the remaining $0.08 is a genuine difference in what the fuel, refining and distribution cost.
Is diesel cheaper in Idaho or Wyoming?
Diesel is cheaper in Wyoming at $5.10 a gallon, against $5.32 in Idaho — $0.21 a gallon apart.
Is it worth crossing from Idaho into Wyoming to fill up?
If you are already near the line, yes: a 15-gallon fill saves about $2.60. Driving out of your way for it rarely pays — at $4.31 a gallon and 25 mpg, a 8-mile round trip would eat the whole saving in fuel alone, before your time.