The Wisconsin gas tax is 30.9 cents per gallon, a state excise charge that applies to gasoline, ethanol blends, and diesel.1Wisconsin Department of Revenue. Motor Vehicle Fuel Tax A separate 2-cent-per-gallon petroleum inspection fee brings total state charges to 32.9 cents, and once you add the 18.4-cent federal excise tax, every gallon of regular gasoline sold in Wisconsin carries 51.3 cents in combined taxes and fees baked into the pump price.
What You Pay Per Gallon
The charges on a single gallon of regular gasoline break down this way:
- State excise tax: 30.9 cents1Wisconsin Department of Revenue. Motor Vehicle Fuel Tax
- Petroleum inspection fee: 2.0 cents2Wisconsin Department of Revenue. Petroleum Inspection Fee
- Federal excise tax: 18.4 cents3Office of the Law Revision Counsel. 26 USC 4081 – Imposition of Tax
That totals 51.3 cents per gallon of gasoline. Diesel drivers pay more federally, 24.4 cents instead of 18.4, so the combined diesel burden runs 57.3 cents per gallon. None of this appears as a line item at checkout. It’s already folded into the posted price per gallon, because the state collects from the first supplier to receive the fuel in Wisconsin, and the cost is passed down to retailers before it ever reaches you.
The excise tax is a flat per-gallon charge, not a percentage. The 30.9 cents stays the same whether the posted price is $2.50 or $4.50, which is the opposite of how a sales tax behaves.
Why the Rate Has Held at 30.9 Cents Since 2006
From 1985 through 2006, Wisconsin indexed the gas tax to automatically rise each year based on fuel prices and inflation.4Wisconsin State Legislature. Motor Vehicle Fuel and Alternative Fuel Tax The 2005 legislature repealed that formula with bipartisan support, and the final indexed adjustment took effect April 1, 2006, locking the rate at 30.9 cents. Any change now requires a new law passed by the legislature, which has not happened in nearly two decades.
Where the Money Goes
Article VIII, Section 11 of the Wisconsin Constitution dedicates all state motor vehicle fuel tax revenue to the Transportation Fund and prohibits the legislature from spending it on anything else.5Justia. Wisconsin Constitution Article VIII – Finance Section 11 – Transportation Fund Motor fuel taxes generate roughly $1.06 billion a year for the fund. A large share flows back to counties, cities, villages, and towns through the General Transportation Aids program to help pay for local road maintenance and construction.6Wisconsin Department of Transportation. General Transportation Aids The rest supports state highways, bridges, transit, and specialized transportation for seniors and people with disabilities.
Who Doesn’t Pay It
Several fuel purchases are exempt from the state motor fuel tax:7Wisconsin Department of Revenue. Motor Vehicle Fuel Tax Information – Publication 307
- Fuel sold to the United States government or its agencies. State and local government purchases are not exempt unless another exemption applies.
- Gasoline or undyed diesel delivered into a bulk storage tank of at least 100 gallons for off-road use in mobile machinery and equipment.
- Dyed (red) diesel sold tax-free for off-road use, including farm vehicles not licensed for highway travel. It cannot legally be used in a highway-licensed vehicle.
- Fuel used by common carriers for urban mass transit.
- Undyed diesel sold or used as heating oil, or used in trains.
- Fuel sold on a tribal reservation to enrolled tribal members.
- The first 1,000 gallons per year of renewable fuel an individual produces for personal use, if none is sold.
If you paid tax on fuel that you then used off-road, you can file Form MF-001 with the Department of Revenue for a refund. The claim must cover at least 100 gallons and be filed within one year of purchase.7Wisconsin Department of Revenue. Motor Vehicle Fuel Tax Information – Publication 307 This matters most to farmers and construction operators who burn significant fuel in equipment that never touches a public road.
EV and Hybrid Surcharges
Drivers of electric and plug-in hybrid vehicles pay little or no gas tax, so Wisconsin collects annual registration surcharges in its place:8Wisconsin Department of Transportation. Vehicle Fuel Surcharge
- $175 per year for fully electric vehicles that cannot run on gasoline, diesel, or alternative fuel.
- $75 per year for hybrid electric vehicles capable of running on both electricity and a combustible fuel.
Both surcharges apply to automobiles and light trucks up to 8,000 pounds gross weight and are collected at registration or renewal. A driver logging 12,000 miles a year in a 30-mpg gasoline car pays about $124 in state fuel tax annually, so the $175 EV surcharge runs somewhat higher than what a typical gas-powered car contributes.
Alternative Fuel Rates
Vehicles running on fuels other than gasoline or diesel owe a separate alternative fuel tax, set lower than the 30.9-cent gasoline rate because these fuels contain less energy per gallon:4Wisconsin State Legislature. Motor Vehicle Fuel and Alternative Fuel Tax
- Liquefied propane gas: 22.6 cents per gallon
- Compressed natural gas: 24.7 cents per gallon equivalent
- Liquefied natural gas: 19.7 cents per gallon
The same exemptions that apply to the regular motor fuel tax, including federal government sales and off-road use, apply to alternative fuels as well.