Every gallon of gas you buy includes a layer of government tax that varies dramatically by where you live. In California, the combined state tax burden exceeds 77 cents per gallon. In Alaska, it is under 9 cents. Understanding this breakdown tells you exactly how much of your fuel budget is funding government programs, how to save on long-distance trips with border fill-up strategy, and what the ongoing policy debates could mean for your future costs.
The Federal Gas Tax: Unchanged Since 1993
The federal gasoline excise tax is 18.4 cents per gallon, last changed in 1993. Diesel carries a higher federal excise of 24.4 cents. Federal taxes flow into the Highway Trust Fund, which finances the Interstate Highway System and federal transportation grants to states.
The 18.4 cents has been severely eroded by inflation. Adjusted for purchasing power, an equivalent amount today would be approximately 38 to 40 cents per gallon. This erosion is the primary reason for the chronic federal infrastructure funding gap: the tax generates less real purchasing power each year while construction and maintenance costs rise. General fund transfers have filled some of the gap in recent legislation.
Highest State Tax Burdens in 2026
| State | Combined State Burden | Key Components |
|---|---|---|
| California | ~77.9 cents/gal | Excise + sales tax + cap-and-trade + LUST fee |
| Pennsylvania | ~58.7 cents/gal | Highest pure excise in the country |
| Washington | ~49.4 cents/gal | Excise + Climate Commitment Act carbon fee |
| Hawaii | ~48.2 cents/gal | State + county taxes combined |
| Illinois | ~45.4 cents/gal | State + Chicago/Cook County local layers |
| Oregon | ~38.0 cents/gal | State excise + first VMT pilot program |
Lowest State Tax Burdens in 2026
| State | State Tax Burden | Note |
|---|---|---|
| Alaska | ~8.95 cents/gal | Lowest tax, but geographic isolation adds distribution cost |
| Mississippi | ~18.8 cents/gal | Among lowest in contiguous states |
| New Mexico | ~18.9 cents/gal | Low excise, no additional carbon fee |
| Missouri | ~19.5 cents/gal | Consistently among lowest |
| Oklahoma | ~19.0 cents/gal | Low excise, benefits from regional refinery proximity |
| Texas | ~20.0 cents/gal + 6.25% sales tax | Low excise but sales tax applies at retail |
Expert Note
For the most current and precise state tax figures, check the American Petroleum Institute's quarterly state motor fuel taxes report at api.org. State legislatures adjust rates periodically, and some states have CPI-indexed automatic adjustments that change rates each year.
What Gas Taxes Pay For
Roads and Bridges
Most state gas taxes are constitutionally or statutorily dedicated to transportation: highway construction, bridge maintenance, and local road funding distributed to counties and municipalities. The federal 18.4 cents goes almost entirely to the Highway Trust Fund for the same purpose.
Public Transportation
Several states direct a portion of gas tax revenue to transit operations. California uses cap-and-trade proceeds partly for transit. New York's MTA receives a portion of fuel tax revenue. This means gas drivers partially subsidize transit systems that compete with driving, a source of ongoing political debate in several states.
Environmental Programs
California's cap-and-trade program funds clean vehicle incentives, transit infrastructure, air quality improvements, and affordable housing near transit. Washington's Climate Commitment Act operates similarly. These programs explicitly link fuel taxes to environmental objectives beyond road maintenance.
Border Fill-Up Strategy
On long drives crossing high-tax states, filling up just before the border can save meaningful money. The tax component difference alone, not counting supply and competition factors, creates predictable price gaps:
- Nevada before entering California: 50 to 70 cents per gallon in state tax component savings
- Indiana or Ohio before entering Illinois, especially before Chicago: state plus local layers compound significantly in Cook County
- Wyoming or South Dakota before entering Colorado or Minnesota: meaningful per-gallon difference
See the most expensive states guide for a complete road trip fill-up strategy by route.
Gas Tax Policy Debates
The gas tax faces structural challenges as vehicles become more fuel-efficient and EVs grow in market share. More efficient vehicles pay less tax per mile driven, reducing revenue without reducing road wear. Several policy responses are being tested or debated: VMT (vehicle miles traveled) fees, which Oregon pioneered with the first state pilot program; higher EV registration fees to replace foregone fuel tax; and indexed fuel taxes that automatically adjust with inflation or inflation-plus.
Gas tax holidays have been implemented by Maryland, Georgia, Connecticut, and New York at various times during price spikes. Research consistently finds approximately 70 to 75 percent of the tax reduction is passed to consumers, with the remainder absorbed by retailers. However, tax holidays cost transportation funding and the relief is temporary.
Pro Tip
Use the Gas Cost Calculator to model how different state tax levels affect your annual fuel cost. Moving from a high-tax to a low-tax state, or planning a long drive through multiple states, can produce surprisingly large differences when calculated over a full year.