Gas Prices in Illinois Today

Gas prices in Illinois are updated weekly. Check back soon for the latest statewide average, or browse our city pages for the most current local data. Historically, Illinois prices track closely with the Midwest regional average.

Illinois charges approximately 66.5 cents per gallon in state excise taxes on gasoline. The federal gas tax adds another 18.4 cents per gallon, bringing the combined tax burden to roughly 84.9 cents per gallon. Illinois's state tax is higher than the national average, which contributes to elevated pump prices statewide.

Nationally, Monday and Tuesday tend to offer the lowest gas prices, while Friday and Saturday are often the most expensive as weekend demand rises. In Illinois, patterns follow similar trends. Prices also fluctuate based on crude oil markets, which reset each week. Checking prices early in the week can save you several cents per gallon.

Illinois borders iowa, wisconsin, indiana, and prices across state lines can vary by 5–30 cents per gallon depending on each state's gas tax, refinery access, and local competition. Illinois's PADD 2 regional supply chain primarily influences local prices. Drivers near state borders may find it worthwhile to cross state lines for a fill-up if price differentials are significant.

Gas prices in Illinois react to several factors: crude oil futures (the biggest driver), local refinery output, seasonal fuel blend mandates, transportation costs to Springfield, and local retailer margins. Prices typically update weekly or more frequently when crude markets are volatile. Summer-blend gasoline, which is more expensive to produce, also raises prices from spring through Labor Day.

Use our station finder on any city page to see real-time prices at nearby stations. Apps like GasBuddy can also show crowdsourced prices. In general, warehouse clubs (Costco, Sam's Club) and hypermarket fuel centers (Walmart, Kroger) consistently offer prices 5–15 cents below branded stations in Illinois. Avoid gas stations directly off major interstates, which typically charge a convenience premium.

Yes, parts of Illinois — particularly densely populated metro areas — are required to use reformulated gasoline (RFG) under EPA clean air standards. RFG burns cleaner but costs slightly more to produce, which adds a few cents per gallon versus conventional gas.

Most vehicles on the road today are designed for regular 87-octane unleaded gasoline. Check your owner's manual — only use premium (91+) if your vehicle requires or recommends it. Using premium when regular is specified wastes money without performance benefit. Midgrade (89 octane) is rarely the optimal choice for any modern vehicle.