The Wisconsin gas tax is 30.9 cents per gallon on gasoline and diesel, a rate that has been frozen since 2006.1Wisconsin Department of Revenue. Motor Vehicle Fuel Tax Add the state’s 2-cent petroleum inspection fee and federal excise taxes, and Wisconsin drivers pay roughly 51.3 cents in combined taxes on each gallon of gasoline and 57.3 cents on each gallon of diesel.
What You Pay Per Gallon
The state fuel tax is a flat 30.9 cents on every gallon of gasoline, gasoline-ethanol blend, and diesel.1Wisconsin Department of Revenue. Motor Vehicle Fuel Tax Because it’s a fixed per-gallon charge rather than a percentage, the state’s cut doesn’t rise when pump prices spike or fall when they drop.
The 2-cent petroleum inspection fee is easy to miss, but it hits every gallon of petroleum product sold in the state.2Wisconsin State Legislature. Wisconsin Code 168.12 – Petroleum Inspection Fee One cent flows to the state transportation fund; the rest supports petroleum tank inspection programs and environmental cleanup.3Wisconsin State Legislature. Petroleum Inspection Fund Informational Paper 71
Federal excise taxes add another layer: 18.4 cents per gallon on gasoline and 24.4 cents on diesel, each of which includes a 0.1-cent Leaking Underground Storage Tank fee.4U.S. Energy Information Administration. Frequently Asked Questions The full stack looks like this:
- Gasoline: 30.9¢ state fuel tax + 2.0¢ petroleum inspection fee + 18.4¢ federal excise = 51.3¢ per gallon
- Diesel: 30.9¢ state fuel tax + 2.0¢ petroleum inspection fee + 24.4¢ federal excise = 57.3¢ per gallon
Why the Rate Has Not Changed Since 2006
Wisconsin used to adjust its gas tax automatically each year for inflation. The legislature created that indexing mechanism in the late 1980s, and for nearly two decades the rate crept upward without a separate vote. A bipartisan coalition repealed indexing in 2005, and the last automatic adjustment took effect on April 1, 2006, locking the rate at 30.9 cents. Any increase now requires the legislature to pass a new bill.
The freeze has held for nearly 20 years. The Wisconsin Legislative Fiscal Bureau has noted that revenue growth in the transportation fund has come largely from increased federal funding and general fund transfers rather than fuel tax collections.5Wisconsin Counties Association. Transportation Delivers Background Information For drivers, the frozen rate means predictable costs year to year.
Where the Money Goes
Nearly all state fuel tax collections flow into the Wisconsin Transportation Fund, a segregated account that can’t be spent on non-transportation purposes. Motor fuel taxes account for about 45% of the fund’s total revenue, with vehicle registration and titling fees making up most of the rest.6Wisconsin State Legislature. Transportation Finance Informational Paper 39
The fund supports several major programs:
- State highway rehabilitation and construction, including major freeway projects in southeastern Wisconsin.7Wisconsin State Legislature. Transportation Budget Summary 2025-27
- General transportation aids under Wis. Stat. § 86.30, which send quarterly payments to every county, city, village, and town to offset local road costs. Calendar year 2026 distributions to municipalities totaled roughly $434 million.8Wisconsin Department of Transportation. General Transportation Aids
- Mass transit and paratransit assistance for public bus systems and specialized transit services for people with disabilities.
- Local road improvement grants, including a separate agricultural roads improvement program for rural infrastructure.
Local governments that receive state transportation aid must deposit those funds in a segregated account used only for highway-related purposes, or they risk forfeiting payments.9Justia Law. Wisconsin Code 86.30 – General Transportation Aids On the federal side, the excise taxes you pay at the pump go to the Highway Trust Fund, which redistributes money back to states through highway and transit grants.
Electric and Hybrid Vehicle Surcharges
Because electric and hybrid vehicles use little or no gasoline, Wisconsin collects annual registration surcharges so these drivers still contribute to road maintenance:
- Full electric vehicles: $175 per year, built from a $100 base surcharge plus an additional $75 surcharge.10Wisconsin State Legislature. Wisconsin Code 341.25 – Vehicle Registration Fees
- Hybrid electric vehicles: $75 per year.11Wisconsin Department of Transportation. Vehicle Fuel Surcharge
Both apply to automobiles and light trucks registered at 8,000 pounds gross weight or less and are collected with your annual registration fee.11Wisconsin Department of Transportation. Vehicle Fuel Surcharge For comparison, a driver covering 12,000 miles a year in a 30-mpg gasoline car pays about $124 in state fuel taxes annually. The $175 EV surcharge roughly tracks that figure, though your own comparison depends on how much you drive.
Getting the Tax Back: Off-Highway Refunds
If you use gasoline or diesel for anything other than driving on public roads, you can claim a refund of the state fuel tax you paid. Farmers running tractors and other field equipment are the most common claimants, and the refund also covers fuel used in boats, stationary engines, and other non-highway equipment.12Justia Law. Wisconsin Code 78.75 – Refund of Motor Vehicle Fuel Tax Two restrictions matter:
- Minimum 100 gallons per claim.
- Twelve-month deadline from the fuel purchase date. Miss it and the refund is permanently lost.12Justia Law. Wisconsin Code 78.75 – Refund of Motor Vehicle Fuel Tax
Claims are filed on Form MF-001 through the Wisconsin Department of Revenue’s My Tax Account portal.13Wisconsin Department of Revenue. MF-001 Instructions – Fuel Tax Refund Claim You’ll need invoices from your fuel supplier showing the purchase date, gallons, and Wisconsin fuel tax paid. The refund is paid to the person named on the supplier’s invoice, so you cannot assign the refund right to someone else.
A narrower exemption covers gasoline and undyed diesel sold directly to the United States government or its agencies.1Wisconsin Department of Revenue. Motor Vehicle Fuel Tax Sales to Wisconsin municipalities and school districts are not exempt, though those entities may still qualify for off-highway refunds on specific fuel use.
Federal Fuel Tax Credit
Separately from Wisconsin’s refund program, the IRS offers a credit for federal excise taxes paid on fuel used off-highway or on a farm, worth 18.3 cents per gallon for gasoline and 24.3 cents per gallon for undyed diesel. You claim it by filing Form 4136 with your federal return.14Internal Revenue Service. Instructions for Form 4136 and Schedule A Dyed diesel, sometimes called “farm diesel,” doesn’t qualify because the federal excise tax was never collected on it. Keep records identifying the equipment each fuel purchase was used for by make and model; the IRS requires that supporting detail.
If You Operate Commercial Trucks
Interstate commercial carriers don’t pay Wisconsin fuel tax the same way ordinary drivers do. If you run qualified motor vehicles across state lines, you likely need to register under the International Fuel Tax Agreement and file a single quarterly return in your base jurisdiction rather than dealing with each state separately. Wisconsin is your base jurisdiction when your vehicles are based here, you keep operational records here, and at least one vehicle travels on Wisconsin highways.15Wisconsin Department of Transportation. International Fuel Tax Agreement Licensed fuel suppliers, meanwhile, handle the actual collection and remittance of the state tax; the tax hits at the distribution level, not at the pump.