Illinois vs Iowa gas prices
Regular gas is $0.52 a gallon cheaper in Iowa — $7.84 on a 15-gallon fill-up. The two share a border, so that gap is worth knowing before you cross it.
Illinois
Iowa| Grade | IL | IA | Diff. | |
|---|---|---|---|---|
| Regular | $4.35 | $3.83 | $0.52IA | Iowa |
| Midgrade | $4.94 | $4.11 | $0.83IA | Iowa |
| Premium | $5.46 | $4.66 | $0.79IA | Iowa |
| Diesel | $5.32 | $4.98 | $0.34IA | Iowa |
Where the $0.52 gap actually comes from
69% of it is tax. Illinois charges $0.36 more per gallon in federal and state taxes than Iowa. The remaining $0.16 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 Local county and city fuel taxes are not included, and Illinois permit them. Pre-tax figures are estimates — see the note below.
What the gap is worth
Based on today’s $0.52 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 Illinois or Iowa?
Regular gas is cheaper in Iowa, at $3.83 a gallon against $4.35 in Illinois — a gap of $0.52, or 13.7%. On a 15-gallon fill-up that is $7.84. Figures are AAA daily state averages for 2026-08-02.
Why is gas more expensive in Illinois?
69% of the $0.52 gap is tax rather than the cost of the fuel. Illinois levies $0.36 more per gallon in federal and state taxes; the remaining $0.16 is a genuine difference in what the fuel, refining and distribution cost.
Is diesel cheaper in Illinois or Iowa?
Diesel is cheaper in Iowa at $4.98 a gallon, against $5.32 in Illinois — $0.34 a gallon apart.
Is it worth crossing from Illinois into Iowa to fill up?
If you are already near the line, yes: a 15-gallon fill saves about $7.84. Driving out of your way for it rarely pays — at $4.35 a gallon and 25 mpg, a 23-mile round trip would eat the whole saving in fuel alone, before your time.