How Truckload Fuel Surcharges Work: The DOE Diesel Index Explained

What is a truckload fuel surcharge?

A truckload fuel surcharge (FSC) is a per-mile charge added to the linehaul rate to cover the cost of diesel. It rises and falls with a published fuel price index, usually every week.

Carriers split fuel out because it is their most volatile cost. A linehaul rate agreed in January would be badly out of date by September 2026 if it had to cover fuel too. The surcharge lets the base rate stay fixed while fuel costs float.

A typical truckload bill looks like this:

• Linehaul: the base rate per mile or per load for moving the freight
• Fuel surcharge: a per-mile charge tied to the diesel index
• Accessorials: extra services or events, such as detention, stops or tarping, if charged separately

How is a truckload fuel surcharge calculated?

Most truckload fuel surcharges use one simple formula with three parts: an index, a peg and a miles-per-gallon number.

Fuel surcharge per mile = (current diesel index - peg) / MPG

• Index: the diesel price the surcharge tracks. The most common is the EIA's weekly U.S. On-Highway Diesel average, often called the DOE index. It posts every Monday.
• Peg (or base): the fuel price assumed to be built into the linehaul rate. Pegs have historically been set near $1.20 per gallon.
• MPG (or escalator): the assumed fuel economy of the truck, often 6 to 6.5 miles per gallon.

Worked example at September 2026 diesel

With the DOE index at $6.529, a $1.20 peg and 6 MPG:

• $6.529 - $1.20 = $5.329
• $5.329 / 6 = about $0.89 per mile

Here is how the surcharge moves with the price of diesel, using the same $1.20 peg.

Some contracts use step tables instead, adding a set amount, such as 1 cent per mile, for every 5 or 6 cents of diesel above the peg. The result is close to the formula. Others use a regional index. The EIA's East Coast average was $6.268 on September 21, about 26 cents below the national figure.

Why are diesel prices so high in 2026?

Diesel is high in 2026 because global supply is tight while demand holds up. On September 7, 2026, the national average hit $5.967, beating the old weekly record of $5.810 from June 2022. Two weeks later it was $6.529.

• Strait of Hormuz disruption: the EIA cited reduced shipments through the strait as a major source of pressure on oil inventories and prices.
• Refinery damage abroad: strikes on Russian refineries and disruptions in the Middle East have cut global fuel supply.
• Tight refining margins: the U.S. diesel crack spread topped $100 per barrel in August 2026, a sign of an unusually tight product market.
• Low inventories: U.S. refineries ran at about 98% in late August, yet distillate stocks sat near 104 million barrels, with East Coast stocks near 19 million.

Fuel prices can fall as fast as they rise, especially if shipping through the Strait of Hormuz returns to normal. That uncertainty is the whole reason surcharges exist.

How much does fuel add to a truckload shipment in 2026?

At the September 21, 2026 DOE price, a standard surcharge adds about $0.89 per mile, or roughly $890 on a 1,000-mile load. Here is what that looks like on common lane lengths from the Carolinas.

Mileage is approximate highway distance. Assumes a $1.20 peg and 6 MPG. Your contract terms may differ.

For a shipper moving 20 loads a week on a 500-mile average lane, the difference between September 2025 and September 2026 diesel is roughly $4,600 a week. That is a budget line finance will ask about.

Fuel surcharge or all-in rate: which is better for shippers?

Neither is always cheaper. They split fuel risk differently. A surcharge passes fuel changes to the shipper week by week. An all-in rate bakes fuel into one number at the time of the quote.

How to compare quotes fairly

Put every quote on the same basis before you choose. Convert surcharge quotes to an all-in number using the current DOE price and the carrier's own FSC table.

1. Take the linehaul rate per mile.
2. Add the FSC per mile at this week's DOE index.
3. Add any accessorials you expect on that lane, such as stop-offs or detention.
4. Compare that total with the all-in quote.

A quote that looks cheap on linehaul can end up higher once fuel and extras are added. With diesel over $6.50, fuel can be a quarter or more of the total bill.

How can shippers lower truckload fuel costs?

Tweaking the surcharge formula rarely works. C.H. Robinson, citing MIT-sponsored research, reports that when shippers push a lower surcharge, carriers raise linehaul rates to make up the difference. The savings come from burning less fuel, not from rewriting the formula.

• Cut dwell time. Trucks idling at a dock burn fuel and hours. See why carriers reject contract loads for how dwell affects cost.
• Fill the trailer. Fewer, fuller loads mean fewer gallons per unit shipped. Our 53-foot dry van dimensions guide covers pallet counts.
• Reduce empty miles. Balanced lanes and backhaul-friendly freight lower what carriers need to charge.
• Plan ahead. Expedited and short-notice loads often mean faster driving and extra deadhead.
• Choose efficient carriers. Newer trucks, speed governors and idle-reduction programs use less fuel per mile.

How does MigWay price fuel on truckload freight?

MigWay quotes one flat, all-in rate with fuel and standard charges included. You get one number up front instead of a linehaul rate plus a weekly-changing surcharge.

• Asset fleet: 400 trucks and 750 trailers, dry van and flatbed.
• Fuel-efficient equipment: 2023-2027 Freightliner, Volvo and Mack automatics, all governed at 70 mph.
• Idle reduction: driver incentives for keeping idle time low.
• Zero outsourcing: every load on our own trucks, so there is no broker margin stacked on top.
• 24/7 in-house dispatch and ELD and GPS tracking on every load.

Want to compare an all-in quote against your current linehaul and FSC? Send us your lanes. Request a freight quote or start a chat with our team, or call +1-980-255-3200.

What is the bottom line on truckload fuel surcharges in 2026?

A truckload fuel surcharge is the diesel index minus a peg, divided by MPG. At September 2026's record diesel, that adds about $0.89 per mile, roughly double a year ago. Compare every quote on an all-in basis, budget for fuel swings, and focus on burning fewer gallons rather than rewriting the formula.

Frequently Asked Questions

What is a fuel surcharge in trucking?

A fuel surcharge is a per-mile charge added to the linehaul rate to cover diesel costs. It moves up and down with a published fuel price index, usually the weekly DOE diesel average.

How do you calculate a truckload fuel surcharge?

Subtract the peg, often about $1.20, from the current DOE diesel price, then divide by the assumed MPG, often 6. At $6.529 diesel, that is about $0.89 per mile.

What is the DOE diesel index?

It is the U.S. Energy Information Administration's weekly average retail price for on-highway diesel. It posts every Monday and is the most common index for truckload fuel surcharges.

What is the current national diesel price?

The EIA reported $6.529 per gallon for the week of September 21, 2026. That was up 24 cents from the prior week and $2.78 higher than a year earlier.

What is a fuel surcharge peg?

The peg is the diesel price assumed to be included in the linehaul rate. The surcharge only covers fuel costs above the peg. Pegs have historically been set near $1.20 per gallon.

Why is diesel so expensive in 2026?

Reduced oil shipments through the Strait of Hormuz, refinery disruptions in Russia and the Middle East, and low distillate inventories have tightened supply. Diesel set a new weekly record on September 7, 2026.

Is an all-in freight rate better than a fuel surcharge?

It depends on how much fuel risk you want to carry. All-in rates give one predictable number for the quote period. Surcharges pass fuel changes through weekly, which helps when diesel falls.

How often do fuel surcharges change?

Most truckload surcharges update weekly, following the Monday DOE release. Some contracts update monthly or use a lagged average to smooth out swings.

Can shippers negotiate fuel surcharges?

Yes, but research cited by C.H. Robinson shows carriers tend to raise linehaul rates when surcharges are cut. Cutting dwell, filling trailers and reducing empty miles saves more.

Does MigWay charge a separate fuel surcharge?

MigWay quotes one flat, all-in rate with fuel and standard charges included. There is no separate weekly fuel line on the invoice.