Fuel Cost Calculator — Diesel Spend by Route
Calculate total diesel fuel spend for any route. Enter distance, fuel economy and current diesel price to get cost per mile and total trip cost.
⛽ Fuel Cost Calculator
How to Use This Calculator
- Enter total miles — for the route or haul. Use Google Maps or your ELD for accurate mileage.
- Enter your MPG — typical loaded semi averages 5.5–6.5 MPG. Use your actual fleet average for accuracy.
- Enter diesel price — use today's pump price or the DOE weekly average for your region.
- Enter truck count — for fleet-level planning, enter the number of vehicles making this run.
Worked Example
An owner-operator runs a 650-mile Chicago–Nashville lane at 6.2 MPG with diesel at $3.95/gal.
- Gallons: 650 ÷ 6.2 = 104.8 gallons
- Fuel Cost: 104.8 × $3.95 = $414.08
- Cost Per Mile: $414.08 ÷ 650 = $0.637/mile
Fuel accounts for roughly $0.64 of every mile — their largest single operating expense. At a load rate of $2.10/mile, fuel alone consumes 30% of revenue.
Pro Tips
Route Optimisation
Avoiding mountainous terrain, urban congestion and unnecessary idling can improve effective MPG by 10–15%.
Fuel Card Discounts
Fleet fuel cards (Comdata, EFS, WEX) typically save $0.15–$0.30/gal at network stops. On 100 gallons that's $15–$30 per fill.
APU for Idling
An Auxiliary Power Unit cuts idling fuel consumption from ~0.8 gal/hr to ~0.25 gal/hr. At 8 hrs/night it saves $1.60/night at $3.85/gal.
Speed Governer
Dropping from 70 to 65 MPH improves fuel economy by roughly 7%. Over a year that's significant savings at scale.
Frequently Asked Questions
A Class 8 semi averages 5.5–7 MPG depending on load weight, terrain, speed, and aerodynamics. Loaded long-haul averages 6–6.5 MPG. Empty deadhead runs average 7–8 MPG. Newer aerodynamic trucks with predictive cruise can hit 8–9 MPG.
The DOE/EIA publishes weekly average diesel prices by region at eia.gov. AAA's Fuel Gauge Report updates daily at fuelgaugereport.aaa.com. GasBuddy shows station-level prices in real time.
For detailed cost accounting, yes. DEF consumption averages 2–3% of diesel consumption (roughly 1 gallon of DEF per 50 gallons of diesel). At ~$2.50/gal for DEF, this adds about $0.05/gal to effective fuel cost.
Fuel typically represents 35–40% of total operating cost for owner-operators. If fuel rises by $0.50/gal and you get 6.5 MPG, your cost per mile increases by $0.077. That's why fuel surcharges exist — to float this variable cost to the shipper.