How to Estimate Fuel Cost for a Trucking Trip

Fuel is usually the biggest bill a truck runs up on a trip, and it's the one that changes fastest. Before you take a load, you want to know how many gallons it'll take and what they'll cost. The math is short. Getting the inputs right is the hard part.

The formula

Gallons = miles ÷ MPG.

Fuel cost = gallons × price per gallon.

With a reefer, add reefer gallons = gallons per hour × hours, times the price you pay for reefer fuel.

Worked example

Say the trip is 1,000 miles, counting the deadhead to the shipper. Your truck averages 6.5 MPG. For the price, use EIA's U.S. average on-highway diesel for the week of September 21, 2026: $6.529 a gallon.

1. Gallons: 1,000 ÷ 6.5 = 153.85 gallons.
2. Fuel cost: 153.85 × $6.529 = $1,004.49.
3. Fuel cost per mile: $1,004.49 ÷ 1,000 = about $1.004 a mile.

A year earlier, for the week of September 22, 2025, the U.S. average was $3.749. The same 153.85 gallons would have cost $576.78. The run hasn't changed, but fuel costs $427.71 more. That's why a rate that worked last fall may not work now.

Adding a reefer

A reefer unit burns fuel by the hour, whether you're rolling or sitting at the dock. Say your unit burns 0.8 gallons an hour (use your own number) and runs 20 hours on this trip.

1. Reefer gallons: 0.8 × 20 = 16 gallons.
2. Reefer fuel: 16 × $6.529 = $104.46.
3. Total fuel: $1,004.49 + $104.46 = $1,108.95, or about $1.109 a mile.

Your reefer's burn rate depends on the unit, the setpoint, the load, and the weather. A frozen load in July burns more than a produce load in October. Check your unit's hour meter against what you put in the reefer tank over a few trips to get a real number.

Getting MPG right

MPG moves the answer more than most people expect. The same 1,000 miles at $6.529:

• At 6.0 MPG: 166.67 gallons, $1,088.19.
• At 6.5 MPG: 153.85 gallons, $1,004.49.
• At 7.0 MPG: 142.86 gallons, $932.73.

Half a mile per gallon is worth $70 to $85 on this one trip. Use your own average from fuel receipts and odometer or ELD miles over the last few months, not the spec sheet. Then think about this load. Heavy freight, mountains, headwind, high speed, and long idle time all pull MPG down. On a heavy or mountain run, use a lower MPG than your average.

Getting the price right

The EIA weekly average is a good starting point because it's published for the whole country and each region, every week. It's a retail average that includes taxes, so it won't match your fuel card price exactly.

Where you fuel matters. For the week of September 21, 2026, EIA's averages ranged widely:

• Gulf Coast: $6.177. The 153.85 gallons would cost $950.33.
• U.S. average: $6.529, $1,004.49.
• California: $8.246, $1,268.65.

If you'll fuel mostly in one region, use that region's price. If your fuel card gives you a discount, take it off. The weekly diesel price pages show every region for each week.

Prices move week to week

A price from last month can be badly out of date. EIA's U.S. average was $5.652 for the week of August 24, 2026, $6.285 for the week of September 14, and $6.529 for the week of September 21. On our 153.85-gallon trip, the one-week rise of 24.4¢ adds $37.54. The four-week rise of 87.7¢ adds $134.93. Use the latest week when you quote a rate, and redo the math when you book loads further out. If prices are climbing fast, pad the price a little rather than hoping it levels off.

Count every mile

Use total trip miles: deadhead to the shipper, the loaded run, and any out-of-route miles you know about. The truck burns fuel on empty miles too, so leaving them out makes the load look better than it is.

What to do with the number

• Compare it to the fuel surcharge on the load. The fuel surcharge calculator shows what the surcharge pays, and this tells you what the fuel really costs.
• Put the fuel cost into the load profit calculator with the rest of your costs to see what the load leaves you.
• Keep your fuel receipts by state. You'll need the gallons for your IFTA return.