How Fuel Surcharges Actually Work (And Why Your Invoice Looks Like That)

Fuel surcharge is one of the most misunderstood lines on a freight invoice. Shippers see a number that changes every week and assume it is negotiable padding. Carriers treat it as a pass-through that keeps rates honest when diesel moves. Both are partly right, and the gap between those views causes more billing disputes than almost anything else in truckload.

Here is how FSC actually works, why it moves, and what to confirm before you agree to a rate.

The FSC exists because diesel is volatile and rates are not

A linehaul rate is negotiated once and then sits still — sometimes for a year on a contract lane. Diesel does not sit still. It can move 30 to 60 cents a gallon in a quarter.

If fuel were baked into the linehaul rate, one of two things would happen. Either the carrier prices in a worst-case fuel assumption and the shipper overpays whenever diesel is cheap, or the carrier prices for today and starts losing money the moment diesel climbs. Neither produces a stable relationship.

Splitting fuel out solves that. The linehaul rate covers the truck, the driver, and the operation. The surcharge floats with actual fuel cost. When diesel drops, the shipper's total cost drops automatically — without renegotiating anything.

Where the number comes from

Almost every FSC program in the United States is anchored to the same source: the DOE/EIA National Average Diesel Price, published by the U.S. Energy Information Administration every Monday afternoon.

That single published number is the reference point. It is public, it is independent, and neither party controls it — which is exactly why the industry settled on it. RAJO's live FSC table is built on that index and refreshes weekly against it.

Two things follow from the Monday publication schedule:

• FSC changes weekly, not daily. A load tendered Thursday uses the rate set by Monday's index, not that morning's pump price.
• There is always a lag. When diesel spikes mid-week, carriers absorb it until the following Monday. When it falls, shippers keep paying the higher rate for a few days. Over time it evens out.

The two ways FSC gets calculated

Per-mile surcharge (truckload standard)

This is what you will see on most FTL and drayage freight. A table maps diesel price ranges to a cents-per-mile figure:

DOE diesel price	Surcharge
$3.60 – $3.69	$0.42 / mile
$3.70 – $3.79	$0.44 / mile
$3.80 – $3.89	$0.46 / mile

The math is straightforward: surcharge per mile × billed miles. A 400-mile load at $0.44 adds $176 in fuel.

The two variables worth arguing about are not the table — it is public — but which miles get billed. Practical, loaded, or dispatched miles can differ by 5 to 10 percent on the same lane. Agree on the mileage source before the first load, not on the first invoice.

Percentage surcharge (LTL and some brokered freight)

Here the surcharge is a percentage of linehaul instead of a per-mile figure. It is simpler to administer but has a real quirk: on a lane where you negotiated a low linehaul rate, the fuel surcharge falls too, even though the truck burned exactly the same diesel. Percentage-based FSC rewards high linehaul rates, which is not what anyone intends.

For truckload and drayage, per-mile is almost always the more honest structure.

Why drayage FSC does not look like truckload FSC

Container work breaks the per-mile model. A drayage move might be 18 miles from ramp to consignee, but the driver spends two hours in a terminal queue with the engine running. Mileage-based fuel recovery does not come close to covering that.

Most drayage programs handle it one of three ways:

1. Flat FSC per move, sized to the market rather than the odometer.
2. A percentage of the linehaul on the drayage rate.
3. FSC folded into an all-in rate, with fuel exposure priced into the base.

None is wrong. What causes disputes is assuming a drayage move will be billed on the same per-mile table as a 600-mile van load. Confirm which structure applies to container freight specifically.

What to confirm before signing

Most FSC disputes trace back to one of these never being written down:

• Which index. DOE national average is standard. Regional indices exist (PADD regions) and run higher in California and the Northeast.
• Which day it resets. Monday publication, but does the new rate apply to loads tendered Monday, picked up Monday, or delivered that week?
• Which miles. Practical, shortest, loaded-only, or dispatched. Name the mileage engine.
• Whether empty miles count. On repositioning and drayage they often should — the fuel was still burned.
• The floor. Below a certain diesel price, most tables go to zero. Know where that is.
• How accessorial moves are treated. Prepulls, chassis splits, and yard pulls may or may not carry FSC.

The honest summary

Fuel surcharge is not margin and it is not a negotiating lever. It is a mechanism for keeping the linehaul rate stable while a volatile input moves underneath it. A carrier that will not explain its FSC calculation, or that uses an index you cannot independently look up, is telling you something.

RAJO publishes its fuel surcharge table openly and updates it weekly against the DOE index. If you want the calculation walked through against a specific lane before you commit, send us the lane and we will show the math.