Gas prices in Illinois today
Regular gasoline in Illinois averages $4.07 per gallon as of Monday, July 13, 2026, 20 cents per gallon above the US national average of $3.87 [EIA · 13 Jul 2026]. On-highway diesel is $4.93, 5 cents off the national diesel mean of $4.88. CPI-indexed excise. Chicago and Cook County stack a 6 c/gal county tax plus city sales tax.
Source: [EIA · 13 Jul 2026] · State excise: 48.3 cents/gal · PADD 2
Illinois's pump-price cost stack
Every gallon you buy at the pump breaks down into five named slices. For Illinois today, the stack looks like this:
Crude / refining / distribution shares estimated from EIA Petroleum Marketing Monthly. Federal excise from FHWA Highway Statistics. State excise from the API Motor Fuel Tax Map and Tax Foundation 2026. [EIA · 13 Jul 2026] [API · 13 Jul 2026]
Border-state comparison
For drivers crossing in or out of Illinois, here is how the neighbours print today:
Use the border comparator to compute the per-tank savings of crossing into a cheaper neighbour, and the round-trip mileage at which the detour pays for itself.
Cheapest metro in Illinois
Today's cheapest metro in Illinois is generally Springfield. Within-state spread is typically 20-40 cents per gallon depending on county tax overlays, station brand and distance from the wholesale rack. AAA publishes metro-level detail for Illinois updated daily.
FAQ
What is the current average price of regular gas in Illinois?
$4.07 per gallon as of Monday, July 13, 2026, 20 cents above the national average. [EIA · 13 Jul 2026]
What is Illinois's state gas tax?
48.3 cents per gallon state excise, plus the 18.4 cents federal excise. [API · 13 Jul 2026]
Where is gas cheapest in Illinois today?
Springfield is typically the cheapest metro. Regional spread is normal at 20-40 cents per gallon.