How fuel cost is calculated
Diesel gallons = trip miles ÷ mpg + idle hours × 0.8 Diesel cost = gallons × diesel price DEF cost = gallons × DEF rate × DEF price Cost per mile = (diesel + DEF) ÷ trip miles
Ways to cut fuel cost
- Drop cruise speed from 70 to 62 mph. It is the biggest single MPG gain for most trucks.
- Use a fuel card with discounts at your usual truck stops.
- Cut idle time with an APU or bunk heater.
- Keep tires at the right pressure and the trailer gap tight.
Common questions
What MPG does a semi truck get?
Most Class 8 trucks get 6 to 8 mpg loaded, depending on weight, speed, terrain and the truck's age.
How much DEF does a truck use?
Typically 2–3% of diesel burned, so about 2–3 gallons of DEF per 100 gallons of diesel.
How do I find today's diesel price?
The U.S. Energy Information Administration publishes the weekly national and regional on-highway diesel average every Monday.