Illinois Gas Price Calculator
Estimate fuel costs and driving expenses in Illinois with the nation's 2nd-highest gas tax
Illinois Calculator
Get accurate results
Updated for 2025 with real Illinois rates, brackets, and regulations
Illinois drivers face the second-highest gas tax in the nation at $0.663 per gallon (combined state motor fuel tax, underground storage tank tax, and environmental impact fee), behind only California. Chicago drivers are hit even harder with additional Cook County ($0.06/gal) and City of Chicago ($0.08/gal) taxes, pushing the total tax burden above $0.80/gallon within city limits. This means Illinois gas prices typically run $0.30-0.50 above the national average. The state doubled its gas tax in 2019 under the Rebuild Illinois capital plan, with annual inflation adjustments built in. Despite the high pump prices, Illinois's flat terrain and extensive expressway network (I-90, I-88, I-55, I-57) make driving the primary mode of transportation outside Chicago. Our calculator estimates your monthly fuel costs and shows how much you're paying in gas taxes alone.
Calculate Your IL Tax
Monthly Gas Cost
146$/mo
Price per Gallon
$4.10
Gallons/Month
35.7
Annual Cost
$1,757
IL Tax/Gallon
$0.663(2nd highest US)
Total Tax/Gal
$0.847
Extra vs National Avg
$300/yr
Breakdown
Insight
Driving 1,000 miles/month at 28 MPG costs $146/month in Illinois. IL has the 2nd highest gas tax in the US at $0.663/gallon (behind California's $0.663). You pay $363/year in gas taxes alone. Chicago adds a city fuel tax on top, making it $0.25-0.35 more than suburban IL. You spend $300 more per year than the national average. Crossing into Indiana for gas saves $0.40-0.50/gallon — popular for border residents near Hammond, East Chicago, and Calumet City.
AI Explanation
What This Means
Based on default inputs, the Illinois Gas Price Calculator shows a monthly gas cost of 146 $/mo. Key figures: Price per Gallon: $4.10, Gallons/Month: 35.7, Annual Cost: $1,757, IL Tax/Gallon: $0.663(2nd highest US), Total Tax/Gal: $0.847, Extra vs National Avg: $300/yr.
Key Insights
Driving 1,000 miles/month at 28 MPG costs $146/month in Illinois. IL has the 2nd highest gas tax in the US at $0.663/gallon (behind California's $0.663). You pay $363/year in gas taxes alone. Chicago adds a city fuel tax on top, making it $0.25-0.35 more than suburban IL. You spend $300 more per year than the national average. Crossing into Indiana for gas saves $0.40-0.50/gallon — popular for border residents near Hammond, East Chicago, and Calumet City.
What You Can Do
Enter your actual figures in the calculator above for a personalized breakdown. Consider consulting a tax professional for comprehensive planning, especially for complex situations involving multiple income sources or deductions.
Keep In Mind
This calculator provides estimates based on 2026 rates. Actual tax liability may vary based on credits, exemptions, and other factors not captured here. This is for educational purposes only and should not be considered tax advice.
How the Illinois Gas Price Calculator Works
The Illinois Gas Price Calculator uses 2026 tax rates, brackets, and deductions specific to Illinois to provide you with an accurate estimate of your tax obligations. Unlike generic federal-only calculators, this tool accounts for the unique tax structure that Illinois residents face.
Formula
Monthly Fuel Cost = (Miles/Month / MPG) x Price/Gallon. IL Gas Tax: $0.663/gal (state) + local taxes (up to $0.14 additional in Chicago). Annual Tax Cost = (Annual Gallons) x Tax Rate.Simply enter your financial details above, and the calculator instantly computes your results using the latest available data. All calculations happen directly in your browser — your personal information is never sent to any server or stored anywhere.
Why Use a Illinois-Specific Calculator?
State-Specific Rates
Uses real 2026 Illinois tax brackets, rates, and thresholds — not generic national averages that miss state-level nuances.
Local Programs & Exemptions
Factors in Illinois-specific programs, exemptions, and deductions that national calculators simply don't account for.
Instant & Private
All calculations run locally in your browser. No account required, no data stored, no waiting for results.
AI-Powered Explanations
Get a plain-English breakdown of your results with actionable insights you can actually use for financial planning.
What's Included
Gas Tax Transparency
See exactly how much of every gallon goes to state and local taxes — $0.66-0.80+ depending on location.
Border Savings Calculator
Estimate savings from filling up in Indiana or Wisconsin where gas taxes are significantly lower.
EV vs Gas Comparison
Illinois's high gas taxes make EVs especially compelling — compare fuel costs including the $100 annual EV fee.
Frequently Asked Questions
Why is gas so expensive in Illinois?
Illinois has the second-highest gas tax in the US at $0.663/gallon (state level). In Chicago, add Cook County ($0.06) and City ($0.08) taxes for a total exceeding $0.80/gallon in taxes alone. The state doubled its gas tax in 2019 through the Rebuild Illinois capital plan and indexed it to inflation, meaning it increases automatically each July 1st. This pushes Illinois gas prices $0.30-0.50 above the national average.
Is it cheaper to get gas in Indiana?
Significantly. Indiana's gas tax is about $0.35/gallon — nearly half of Illinois's $0.663. This creates a $0.30-0.40/gallon price difference at stations near the border. Illinois drivers in the south suburbs and Chicago Southland routinely drive to Hammond, Munster, or Dyer, IN for cheaper gas. On a 15-gallon fill-up, you save $4.50-6.00 per trip.
How much do Illinois drivers pay in gas taxes per year?
The average Illinois driver uses about 500-600 gallons per year. At $0.663/gallon state tax, that's $330-400/year in state gas taxes alone. Chicago drivers paying the full $0.80+/gallon in total taxes spend $400-480/year on gas taxes. A family with two cars easily pays $700-900/year in gas taxes — more than many states charge in vehicle registration.
Does Illinois have toll roads that add to driving costs?
Yes. The Illinois Tollway system covers 294 miles of expressways in the Chicago metropolitan area, including I-90, I-88, I-355, and I-294. I-PASS transponder users save about 50% over cash tolls. A typical Chicago-area commuter using tollways pays $50-150/month in tolls. Combined with high gas taxes, driving costs in the Chicago area are among the highest in the Midwest.
Should I switch to an electric vehicle in Illinois?
Illinois's high gas taxes make the switch particularly compelling. At $3.75/gallon and 28 MPG, a gas car costs $0.134/mile. An EV at 3.5 miles/kWh and $0.14/kWh (ComEd rate) costs just $0.04/mile — saving 70%. On 12,000 miles/year, that's $1,128 in fuel savings. Illinois charges a $100 annual EV registration fee (lower than many states). Net annual savings: roughly $1,000+.
Important Information for Illinois Residents
Tax laws in Illinois can change annually. This calculator is updated regularly to reflect the latest 2026 rates and regulations, but you should always verify important financial decisions with a qualified Illinois tax professional or CPA.
This tool is designed for informational and educational purposes. While we strive for accuracy using official Illinois Department of Taxation data, the results should be used as estimates for planning purposes only. Your actual tax liability may differ based on credits, special circumstances, and legislative changes that occur after our last update.
For filing deadlines, payment schedules, and official forms, visit the Illinois Department of Taxation and Finance website. If you have complex tax situations involving multiple states, business income, or significant investment gains, professional guidance is recommended.
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