Dispatch notes · 2026-09-26

Quick answer: A fuel surcharge (FSC) is a separate line item on your freight invoice that adjusts with diesel prices, so carriers don't have to rebuild their entire rate structure every time fuel costs move. It's typically calculated using a published index — most commonly the U.S. Energy Information Administration's weekly diesel price average — and applied as a percentage of the linehaul rate or a cents-per-mile figure. You can verify it, budget for it, and negotiate its terms before a load ever ships. It's not arbitrary, and a shipper who understands the formula can catch billing errors fast.

Key takeaways

• Most fuel surcharges reference the EIA's weekly U.S. average on-highway diesel price, published every Monday, or a regional OPIS index — not a number the carrier picks.
• Surcharges usually reset weekly and apply against a baseline price; once diesel crosses that baseline, the surcharge scales up in tiers or per-cent increments.
• Full truckload (FTL) surcharges are typically calculated per mile, while LTL surcharges are usually a percentage of the linehaul charge — the two aren't directly comparable.
• Ask for the surcharge table in writing before you book a lane; a carrier that can't produce one is asking you to trust a number you can't check.

Step 1: Understand why the surcharge exists at all

A fuel surcharge exists because diesel prices move faster than freight rates can be renegotiated. Linehaul rates in a full truckload shipping contract are often set for months at a time, but diesel can swing by double digits in a matter of weeks. Without a surcharge, carriers would either eat the loss when fuel spikes or pad every rate with a cushion that overcharges shippers when fuel is cheap.

The fuel surcharge separates two costs that behave differently:

• The linehaul rate — pays for the truck, the driver, the equipment, and the margin. This stays relatively stable.
• The fuel surcharge — pays for the diesel burned on that specific run. This moves with the market.

Splitting them out means a shipper isn't stuck negotiating a whole new rate every time fuel jumps. It also means when diesel drops, the shipper's invoice drops with it — the surcharge cuts both ways. That's the core distinction from a flat markup: a markup only goes one direction. A surcharge tied to a published index goes down as often as it goes up, which is why regulators and shipper associations generally treat it as a legitimate pass-through mechanism rather than a hidden profit center.

We go deeper on the mechanics of surcharge resets and why they change week to week in How Fuel Surcharges Work in Freight and Why They Change.

Step 2: Find out which index and baseline your carrier uses

Ask your carrier two questions before you sign a rate confirmation: which index they reference, and what baseline diesel price triggers the surcharge. Most carriers in the U.S. tie their FSC to the EIA's weekly retail on-highway diesel fuel price, published every Monday for the prior week, because it's free, public, and updated on a predictable schedule. Some carriers use OPIS (Oil Price Information Service) data instead, which updates more frequently and is common in contracts with brokers or large shippers who want daily granularity.

Either way, the surcharge formula generally works like this:

• A baseline diesel price is set in the contract (for example, a price per gallon below which no surcharge applies).
• Each week, the current index price is compared to that baseline.
• The difference is converted into a surcharge — either a flat cents-per-mile add-on for full truckload freight, or a percentage of the linehaul charge for less-than-truckload freight.
• The new surcharge rate applies to shipments picked up during that index week, not retroactively to loads already delivered.

Don't skip this: if a carrier can't tell you the baseline price and the index they reference, you have no way to check whether the surcharge on your invoice is fair. Get the formula in writing before the truck is dispatched, not after the invoice arrives.

Step 3: Know when the surcharge applies to your shipment

Fuel surcharges apply differently depending on the type of freight and the lane. For full truckload dry van and reefer freight, the surcharge is almost always distance-based — calculated in cents per mile and added to the linehaul charge for the total loaded miles. For LTL freight, it's usually a percentage tacked onto the base rate, since LTL pricing already bundles multiple cost factors together.

Here's how that typically breaks down across service types:

A few situations where fuel surcharge terms often work differently:

• Dedicated lanes running the same route repeatedly may lock in a surcharge that resets monthly rather than weekly, since both sides can plan around a known volume.
• Very short-haul or drayage moves sometimes carry a flat surcharge instead of a mileage-based one, because the fuel cost per mile doesn't scale the same way over 50 miles as it does over 800.
• Multi-stop truckload routes may calculate the surcharge on total routed miles rather than a straight point-to-point distance — worth confirming before you book a load with several delivery stops.

If you're comparing quotes across carriers, remember that a lower linehaul rate paired with a poorly disclosed surcharge can end up costing more than a transparent, slightly higher all-in rate. Our post on what drives full truckload shipping costs walks through the other line items that shape your total invoice beyond fuel.

Step 4: Check the surcharge against your bill of lading and invoice

Verify the surcharge by pulling three numbers: the index price for your pickup week, the baseline in your contract, and the rate applied on the invoice. The math should be reproducible — if it isn't, that's your cue to call your carrier or broker and ask for the calculation.

Here's a simple way to check it yourself:

• Confirm the pickup date on your bill of lading, since the surcharge is tied to the index week the freight moved, not the invoice date.
• Look up the EIA's published diesel average for that week (or ask your carrier which index they used).
• Subtract the contract's baseline price from that week's index price.
• Multiply the difference by the agreed rate-per-cent (for example, "$0.01 for every $0.05 above baseline").
• Compare that result to the cents-per-mile or percentage shown on your invoice.

If the numbers don't match, it's usually a timing issue — the wrong index week got applied — rather than an intentional overcharge. Most carriers will correct it quickly once you show your math. For a broader walkthrough of everything else that should appear on that document, see How to Read Your Freight Bill of Lading.

Step 5: Budget for and negotiate surcharge terms before you book

Lock in the surcharge formula in writing at the same time you negotiate the linehaul rate, not after. A rate confirmation that only states "plus applicable fuel surcharge" with no index, no baseline, and no update frequency gives you nothing to verify later.

When you're setting up a new lane or annual contract, ask for:

• Gather the specific index (EIA weekly average or OPIS) the carrier uses.
• Confirm the baseline diesel price that triggers the surcharge.
• Get the update frequency in writing — weekly is standard, but dedicated lanes sometimes use monthly resets.
• Ask whether the surcharge applies to loaded miles only or total routed miles on multi-stop runs.
• Request a sample calculation using a recent week's actual index price, so you can see the formula work in practice.
• Set a review date if you're locking in a long-term or dedicated freight contract, so the baseline can be revisited if diesel prices shift structurally.

Diesel prices have been volatile enough in recent periods that even a well-structured surcharge can produce a noticeably different invoice from one quarter to the next. That volatility is exactly why the surcharge exists — it protects the shipper from carriers padding rates defensively, and it protects the carrier from running loads at a loss. We cover how diesel price swings ripple into transit planning and cost forecasting in How Diesel Prices Change Your Freight Costs and Timing.

If you're building a shipping budget for the next few quarters, model two scenarios — one at current diesel prices and one at a reasonable higher range — so a surcharge swing doesn't blow up your freight budget mid-contract.

Where PST Logistics fits into this

PST Logistics runs full truckload dry van and temperature-controlled freight out of Naperville, Illinois, with the same truck and same driver from pickup to delivery — no cross-docking, no transloading, and no layers between the driver and the dispatcher who quoted your rate. That matters for fuel surcharge transparency specifically: when one carrier handles the entire run, there's one surcharge calculation to verify, not several stacked across different legs and different carriers. Shippers and brokers who need a rate quote, a sample surcharge calculation, or an insurance certificate can reach PST's 24/7 dispatch by phone or through the online rate request form.

Checklist: Verifying and negotiating your fuel surcharge

• Ask your carrier which index (EIA or OPIS) they use before booking a lane.
• Get the baseline diesel price and update frequency in writing on the rate confirmation.
• Confirm the pickup date on your bill of lading matches the index week billed on your invoice.
• Recalculate the surcharge yourself using the published index price for that week.
• Clarify whether multi-stop or dedicated routes use total routed miles or point-to-point distance.
• Request a sample calculation from your carrier before signing a long-term contract.
• Set a review date for baseline pricing on any dedicated or annual freight agreement.
• Flag any invoice where the math doesn't reproduce and ask for a corrected version in writing.

Related articles

• How Fuel Surcharges Work in Freight and Why They Change
• What Drives Full Truckload Shipping Costs
• How Diesel Prices Change Your Freight Costs and Timing

More dispatch notes How Diesel Prices Change Your Freight Costs and Timing Dry van and temperature-controlled capacity Safety and compliance at PST Global Where we run: all 48 states Request a quote from dispatch