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Colorado Gas Tax Calculator

Colorado charges 29.2¢/gal on gasoline and 34.7¢/gal on diesel (all state taxes and fees). Combined with the federal tax, drivers in Colorado pay 47.7¢/gal total on gasoline. The base excise rate is 22.0¢/gal.

CO gasoline (combined)

29.2¢

excise: 22.0¢

CO diesel (combined)

34.7¢

excise: 20.5¢

Federal gasoline tax

18.5¢

18.4¢ excise + 0.1¢ LUST

Combined (gas + federal)

47.7¢

Includes excise + all state fees and surcharges (29.2¢/gal).

Federal gasoline excise18.4¢/gal
Federal LUST fee0.1¢/gal
Colorado combined29.2¢/gal
↳ of which excise22.0¢/gal
Combined rate47.7¢/gal
Rates updated for June 2026

Tax on 15 gallons of gasoline in Colorado(all fees)

Federal tax

$2.77

Colorado tax

$4.38

Total tax

$7.15

This calculator is for informational purposes only and does not constitute tax advice. Consult a qualified tax professional for your specific situation. Rates last verified June 2026.

Verify rates on Colorado Department of Revenue — Fuel Tax

Gas tax per fill-up in Colorado

State column uses the combined rate (29.2¢/gal, all fees). Excise-only rate is 22.0¢/gal.

Tank sizeState taxFederal taxTotal tax
10 gallons$2.92$1.85$4.77
12 gallons$3.50$2.22$5.72
15 gallons$4.38$2.77$7.15
18 gallons$5.25$3.33$8.58
20 gallons$5.84$3.70$9.54
25 gallons$7.29$4.63$11.92
30 gallons$8.75$5.55$14.30

Gasoline only. State tax uses combined rate (all fees). Federal includes 18.4¢ excise + 0.1¢ LUST fee.

Colorado note: Excise rate reflects the base statutory rate. Combined rate accounts for the core excise plus active HUTF fees, Bridge and Tunnel Impact fees, and indexed state Road Usage Fees.

Frequently asked questions

What is the gas tax in Colorado?
Colorado's state gasoline tax is 29.2¢ per gallon (all fees included; excise-only is 22.0¢) and the diesel tax is 34.7¢ per gallon (excise-only: 20.5¢). Combined with the federal 18.4¢/gal gasoline excise and 0.1¢/gal LUST fee, drivers in Colorado pay a total of 47.7¢ per gallon of gasoline in state and federal taxes.
How much gas tax do I pay on a full tank in Colorado?
On a 15-gallon fill-up with gasoline in Colorado, you pay approximately $4.38 in state taxes (all fees) plus $2.77 in federal tax — a combined total of $7.15 in taxes per fill-up. Use the calculator above to adjust for your tank size.
What is the difference between Colorado's excise tax and combined tax on fuel?
Colorado's gasoline excise tax is 22.0¢/gal — this is the pure statutory per-gallon tax set by the state legislature. The combined rate of 29.2¢/gal includes the excise plus additional state-level fees such as environmental surcharges, petroleum storage tank fees, or sales tax components. The combined rate is what drivers effectively pay per gallon.
What is the federal gas tax in 2026?
The federal gasoline excise tax is 18.4 cents per gallon and has been unchanged since October 1, 1993. The federal diesel excise tax is 24.4 cents per gallon. An additional 0.1 cent per gallon Leaking Underground Storage Tank (LUST) fee also applies to both fuels, bringing the combined federal rate to 18.5 c/gal (gasoline) and 24.5 c/gal (diesel). These taxes fund the Highway Trust Fund for interstate highway maintenance and mass transit.
What is the difference between excise rate and combined rate?
The excise rate is the pure statutory per-gallon excise tax set by the state legislature. The combined rate is the total state-level tax burden per gallon as compiled by the EIA, including the excise tax plus environmental fees, petroleum storage tank fees, inspection fees, and in some states an applicable sales tax on fuel. For most states the difference is small (under 2 c/gal), but states like California, Indiana, Illinois, Vermont, and Washington D.C. show significant gaps because they layer sales taxes or large surcharges on top of the excise.
Which state has the highest gas tax?
California has the highest combined state gas tax at 70.9 cents per gallon as of January 1, 2026, per the EIA. This includes the excise tax plus the 2.25% sales tax on gasoline. California also has the highest combined diesel tax at 87.3 c/gal. Illinois (66.4 c/gal gasoline) and Washington (59.04 c/gal) rank second and third.

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