Colorado diesel tax rate is 20.5¢ per gallon for 2026. Calculate your quarterly IFTA fuel tax liability for Colorado routes and compare to neighboring states.
Calculate Your Colorado IFTA Tax
Gallons consumed in Colorado→
Net taxable gallons→
Colorado tax rate (2026)→20.5¢/gal
Estimated Colorado IFTA→
Positive = amount owed to Colorado; negative = credit on your quarterly return. This is one component of your full multi-state IFTA filing.
Colorado IFTA Rates & Trucking Overview 2026
Colorado's diesel rate of 20.5¢/gal is among the lowest in the nation — only Missouri, Oklahoma, Texas, Louisiana, and Mississippi are cheaper. Denver is a major distribution hub for the Mountain West, and I-70 through the Rockies is one of the most challenging (and critical) freight routes in the country.
Major Colorado Trucking Routes
I-25 (Denver–Pueblo–New Mexico, north-south spine), I-70 (Kansas City–Denver–Grand Junction–Utah, primary east-west mountain corridor), I-76 (Denver–Nebraska), I-80 (runs through NE corner)
I-70 through the Eisenhower/Johnson Tunnel and the mountain passes requires careful trip planning — commercial trucks face seasonal restrictions, chain laws, and hazardous conditions. The Denver metro's warehouse boom along I-25 and E-470 has made Colorado one of the fastest-growing regional distribution markets. Kansas neighbors Colorado to the east at 26.0¢, making Colorado the better fueling choice on that border.
Colorado IFTA — Frequently Asked Questions
What is Colorado's IFTA diesel tax rate in 2026?
Colorado's diesel rate is 20.5¢/gal for 2026 — 5th lowest in the US. All neighboring states have higher rates, making Colorado a consistent fueling value for cross-country drivers.
Who administers IFTA for Colorado-based carriers?
Colorado IFTA is administered by the Colorado Department of Revenue. File quarterly at Colorado.gov/Revenue. Late filing carries a penalty of 10% of net tax due or $50, whichever is greater.
Are there truck restrictions on I-70 through Colorado?
Yes. I-70 through the mountains has seasonal chain requirements and commercial vehicle restrictions. Eisenhower Tunnel (11,013 ft) has restrictions for hazmat. Check CDOT at cotrip.org before dispatching mountain loads.
Why is Colorado's diesel tax so low?
Colorado has a flat 20¢/gal excise tax on diesel with a small 0.5¢ inspection/cleanup fee, for a 20.5¢ effective IFTA rate. The state has not significantly raised this rate in decades, making it one of the most trucker-friendly states in the Rocky Mountain region.
Fueling tip: At 20.5¢/gal, Colorado is a great place to fuel. On I-70 runs, fill up in Colorado before heading into Utah (31.9¢) or fill before entering Kansas (26.0¢) eastbound. Wyoming to the north is 24.0¢ — still higher than Colorado.