The short answer
Fuel cost per mile equals the diesel price divided by your miles per gallon. A loaded semi averaging about 6.3 mpg with diesel at $6.00 a gallon spends about $0.95 per mile on fuel. Diesel can differ by more than $2 a gallon between the cheapest and most expensive states, so where you fuel up matters.
Fuel is one of the biggest bills an owner-operator pays, and it changes every day. Two numbers decide what it costs you: the price per gallon and your miles per gallon. You control more of both than you might think.
Your fuel cost per mile
The formula is simple:
Fuel cost per mile = diesel price per gallon / miles per gallon
A loaded semi averaging about 6.3 mpg (the FHWA national average for combination trucks) with diesel at $6.00 a gallon spends about $0.95 per mile on fuel. On a 2,500-mile week that is close to $2,400.
Smaller trucks do better per mile but carry less. A hotshot averaging around 9-10 mpg loaded, or a 26 ft box truck at 8.5-11 mpg, spends roughly half as much per mile as a semi.
Try your own truck, weight and state in the truck fuel cost calculator.
Why diesel prices differ by state
Diesel can differ by more than $2 a gallon between the cheapest and most expensive states. The main reasons:
- State fuel taxes. These vary widely and are built into the pump price.
- Distance from refineries and pipelines. Gulf Coast states such as Texas, Louisiana and Mississippi are close to refining capacity.
- Fuel specifications. California requires its own cleaner blend and has additional fees, which is why it is usually the most expensive.
- Local competition at truck stops along major corridors.
See today's diesel prices for all 50 states, updated every day, or look up a single state such as diesel prices in Texas.
Seven ways to cut fuel cost per mile
- Plan fuel stops by state. Filling 150 gallons where diesel is $1 cheaper saves $150 on one stop.
- Cut deadhead miles. Empty miles burn fuel with no revenue. Planning the next load before this one delivers is the single biggest lever.
- Slow down. Above about 62 mph, a semi loses roughly 0.1 mpg for every extra mph.
- Idle less. A semi burns about 0.8 gallons per hour at idle.
- Keep tires properly inflated and check alignment.
- Know your load weight. NACFE research puts the fuel penalty at about 0.5-0.6% for every extra 1,000 lbs.
- Book loads that cover fuel. Know your fuel cost per mile before accepting a rate.
How a dispatcher helps
A good dispatcher plans lanes to reduce empty miles and negotiates rates that leave room after fuel. At Texas Solutions, semi truck dispatch is 5% of weekly gross, hotshot dispatch 8% and box truck dispatch 10%. See what it would cost you.
Frequently asked questions
Why is diesel cheaper in some states?
State fuel taxes, distance from refineries and pipelines, local fuel specifications and competition all affect the pump price. Gulf Coast states near refineries are usually among the cheapest; California is usually the most expensive.
How do I calculate fuel cost per mile?
Divide the diesel price by your truck's miles per gallon. For example, $6.00 a gallon divided by 6.3 mpg is about $0.95 per mile.
What mpg does a loaded semi get?
The FHWA national average for combination trucks is about 6.3 mpg. Heavier loads, higher speeds and idling lower it; lighter loads and slower highway speeds raise it.