Diesel fuel is typically the second-largest expense for a trucking company after the truck itself, commonly running 20% to 25% of total operating costs. Unlike a truck payment, which stays fixed for years, fuel prices move week to week based on factors well outside any individual carrier's control, which makes budgeting for it a genuinely different kind of challenge.
Carriers who plan deliberately around fuel volatility protect their margins far better than those who simply absorb whatever the pump charges each week.
In This Guide
1. Why Diesel Prices Swing
Diesel prices move based on crude oil prices, refining capacity, seasonal demand shifts, and broader supply disruptions, none of which a single carrier has any control over. Prices can swing meaningfully over just a few months, which is exactly why a fuel budget based on a single snapshot price is usually wrong within a quarter.
2. Fuel's Share of Operating Costs
A loaded semi-truck typically gets 6 to 8 miles per gallon, meaning a truck running 100,000 miles a year burns somewhere around 13,000 to 17,000 gallons of diesel annually. At typical pricing, this makes fuel one of the largest and most variable line items in a carrier's entire cost structure, second only to the truck payment or lease itself.
3. How Fuel Surcharges Help
Most freight rates include a separate fuel surcharge, calculated against a published national average diesel price and adjusted weekly or monthly, specifically to pass fuel volatility through to the shipper rather than leaving the carrier to absorb it alone. Our guide on how fuel surcharges are calculated breaks down exactly how this adjustment works and what to check for in a rate confirmation.
Not every load includes a fuel surcharge, and the formulas brokers use can vary. Confirming the surcharge basis before accepting a load protects a carrier from quietly absorbing a fuel price spike mid-contract.
4. Practical Budgeting Approaches
Rather than budgeting off a single current price, many carriers build their cost-per-mile calculations around a rolling average of the past several months, with a buffer built in for upward swings. Tracking the published national average diesel price weekly, available through the US Energy Information Administration, helps a carrier spot a trend early rather than being surprised by it after several weeks of rising costs.
5. Improving Fuel Efficiency
Since fuel cost is a direct function of miles driven divided by miles per gallon, efficiency improvements have a direct and immediate effect on the fuel budget. Reducing idle time, maintaining proper tire pressure, and driving at moderate highway speeds rather than the top of the speed limit all measurably improve a truck's real-world fuel economy over a full year of driving.
6. Fuel Cards and Discounts
Commercial fuel cards, offered by major truck stop chains and dedicated fuel card providers, typically offer a per-gallon discount at participating stations in exchange for a account relationship, and many also consolidate fuel purchase tracking into a single monthly statement that simplifies accounting. For a truck running significant annual mileage, these discounts can add up to a meaningful reduction in the year's total fuel spend.
Frequently Asked Questions
What percentage of trucking operating costs is fuel?
Fuel typically represents about 20% to 25% of a trucking company's total operating costs, making it usually the second-largest expense category after the truck payment or lease itself.
Do fuel surcharges actually cover fuel cost increases?
Fuel surcharges are designed to pass fuel price volatility through to the shipper, calculated against a published national average diesel price. How well a specific surcharge formula tracks actual cost increases varies by the terms in the rate confirmation, which is worth checking before accepting a load.
How can a small carrier reduce fuel costs?
Reducing idle time, maintaining proper tire pressure, driving at moderate highway speeds, and using a commercial fuel card for per-gallon discounts are all practical, low-cost ways carriers improve real-world fuel economy and reduce the effective cost per mile.
This guide is for informational purposes. Regulations, fees, and requirements change — always verify current information directly with the FMCSA, your state DOT, and qualified professional advisors before making business decisions.