Colorado drivers pay 27 cents per gallon in state tax on gasoline and 32.5 cents per gallon on diesel through June 30, 2026. Both rates rise by a penny on July 1, 2026, when the state’s road usage fee steps up on its scheduled path. Federal excise tax adds another 18.4 cents on gasoline and 24.4 cents on diesel, so the full government take is roughly 45 cents per gallon of regular and 57 cents per gallon of diesel.
The Base Excise Tax
Colorado’s excise tax on gasoline is 22 cents per gallon. Diesel, which the statute calls “special fuel,” is taxed at 20.5 cents per gallon.1Justia. Colorado Code 39-27-102 – Tax Imposed on Gasoline and Special Fuel These have held steady since 2022 with no change scheduled.
Distributors remit the tax before fuel reaches the retail station, so the charge is already built into the pump price. The Department of Revenue oversees compliance, and distributors who fail to remit face license revocation or civil fines.
The Road Usage Fee
Senate Bill 21-260, signed in 2021, added a road usage fee on top of the excise tax. It’s codified at C.R.S. § 43-4-217 and climbs by about a penny each year.2Justia. Colorado Code 43-4-217 – Road Usage Fees Through June 30, 2026, the fee is 5 cents per gallon. On July 1, 2026, it rises to 6 cents.3Department of Revenue – Taxation. Fuel Tax and Fee Rates The scheduled increases continue through fiscal year 2031-32, when the fee reaches 8 cents per gallon.
The fee applies to gasoline and diesel. It does not apply to aviation fuel, compressed natural gas, liquefied natural gas, or propane.3Department of Revenue – Taxation. Fuel Tax and Fee Rates
The Bridge and Tunnel Impact Fee
SB 21-260 also created a bridge and tunnel impact fee, charged only on diesel and other special fuels. Gasoline is not subject to it, and dyed diesel for off-road use is exempt. The rate is 7 cents per gallon through June 2027.3Department of Revenue – Taxation. Fuel Tax and Fee Rates This is the main reason diesel carries a noticeably heavier state tax load than gasoline in Colorado.
Combined State Totals for 2026
Adding the excise tax, road usage fee, and (for diesel) the bridge and tunnel impact fee gives the per-gallon totals collected at the state level:
- Gasoline, January through June 2026: 22 + 5 = 27 cents per gallon
- Gasoline, July through December 2026: 22 + 6 = 28 cents per gallon
- Diesel, January through June 2026: 20.5 + 5 + 7 = 32.5 cents per gallon
- Diesel, July through December 2026: 20.5 + 6 + 7 = 33.5 cents per gallon
These figures don’t include the environmental response surcharge, which is assessed on distributors per truckload rather than per gallon and adds only fractions of a cent to retail prices.3Department of Revenue – Taxation. Fuel Tax and Fee Rates The surcharge is $25 per tank truckload when the Petroleum Storage Tank Fund balance is below $8 million, and zero when the fund exceeds that threshold.4Justia. Colorado Code 8-20-206.5 – Environmental Response Surcharge
Federal Excise Tax on Top
The federal government layers its own excise tax over the state’s under 26 U.S.C. § 4081. Gasoline is taxed at 18.3 cents per gallon plus a 0.1-cent Leaking Underground Storage Tank surcharge, for 18.4 cents total. Diesel is 24.3 cents plus the same 0.1-cent LUST surcharge, or 24.4 cents total.5Office of the Law Revision Counsel. 26 USC 4081 – Imposition of Tax These rates have not changed since 1993 and are not indexed for inflation.
Combined with the state charges, a Colorado driver pays roughly 45 to 46 cents per gallon on regular gasoline in 2026, and roughly 57 cents per gallon on diesel. The charges are folded into the posted price, so you don’t see them itemized at the pump.
Rates on Other Fuels
Aviation fuel is taxed at 6 cents per gallon for piston-engine aircraft and 4 cents per gallon for jet and turboprop fuel.1Justia. Colorado Code 39-27-102 – Tax Imposed on Gasoline and Special Fuel Aviation fuel is not subject to the road usage fee or the bridge and tunnel fee. Revenue goes to the Colorado Aviation Fund, which pays for runway repairs, safety upgrades, and navigation equipment at public-use airports.6Colorado General Assembly. Aviation Fuel Tax
Alternative motor fuels are taxed at lower rates that reflect their lower energy content per gallon:1Justia. Colorado Code 39-27-102 – Tax Imposed on Gasoline and Special Fuel
- Propane (LPG): 13.5 cents per gallon
- Compressed natural gas (CNG): 18.3 cents per gallon equivalent
- Liquefied natural gas (LNG): 12 cents per gallon
These rates have applied since January 1, 2019, following a multi-year phase-in. Because the road usage fee doesn’t reach CNG, LNG, or propane, the excise tax is the only state per-gallon charge on those fuels.3Department of Revenue – Taxation. Fuel Tax and Fee Rates
Who Doesn’t Pay, and Who Can Get a Refund
Fuel purchased by federal agencies, state agencies, cities, counties, school districts, and other political subdivisions is exempt from the excise tax when used exclusively for governmental functions.7Department of Revenue – Taxation. Fuel Tax Topics – Fuel Users
Private buyers who use fuel off-highway can claim a refund. Farming, off-road construction, and stationary equipment are the most common qualifying uses. You need a refund permit from the Department of Revenue and must file claims on the required schedule.7Department of Revenue – Taxation. Fuel Tax Topics – Fuel Users Detailed records of every off-highway gallon are essential; the Department audits refund claims, and missing documentation is the fastest way to lose one. Certain commercial and commuter air carriers can also claim refunds on aviation fuel if they meet specific federal certification requirements.
Federal refunds for non-highway use go through IRS Form 8849. The minimum claim is $750; smaller amounts roll forward to the next quarter.
Electric Vehicles
Electric vehicles don’t buy gasoline or diesel, so they don’t pay any of the per-gallon charges above. Colorado captures road funding from EV owners through an annual registration-based road usage fee that varies by vehicle weight, with passenger EVs paying a base amount and heavier commercial EVs paying more. The charge appears on the DMV registration renewal notice.