Fuel surcharges explained: how carriers calculate them and how to negotiate a fair table
How truckload, LTL and parcel fuel surcharges work, the formula behind a per-mile surcharge, worked examples at current diesel prices, and what procurement should put in carrier contracts.
Key takeaways
- Most truckload fuel surcharges use the weekly U.S. average diesel price from the Energy Information Administration (EIA).
- A common formula is (current diesel price − base price) ÷ assumed miles per gallon, charged per mile.
- The base price and mpg assumption matter as much as the diesel price; standardize them across carriers to compare bids.
- LTL and parcel carriers usually charge fuel as a percentage of linehaul or transportation charges, set by their own published tables.
- Audit surcharges against the table every week; small errors compound across thousands of loads.
In this guide
Why fuel surcharges matter more now
Diesel set a record above $6.50 a gallon in September 2026 and was about $6.18 in mid-October, according to EIA data reported by FreightWaves. With fuel that high, the surcharge can be a third or more of the cost of a truckload, and small differences in how it’s calculated add up quickly. See our diesel outlook.
How truckload fuel surcharges work
Most truckload contracts charge fuel per mile using a simple formula:
Fuel surcharge per mile = (current diesel price − base price) ÷ miles per gallon
- Current diesel price: usually the EIA weekly U.S. on-highway diesel average, national or regional, published each Monday.
- Base price (“peg”): the diesel price assumed to be included in the linehaul rate. Below it, no surcharge applies.
- Miles per gallon: the fuel economy the formula assumes, often between 5 and 7.
Worked examples
Using a $1.25 base and 6.5 mpg:
| Weekly diesel price | Surcharge per mile | On a 500-mile load | On a 1,000-mile load |
|---|---|---|---|
| $4.00 | $0.42 | $212 | $423 |
| $5.00 | $0.58 | $288 | $577 |
| $5.50 | $0.65 | $327 | $654 |
| $6.18 | $0.76 | $379 | $758 |
| $6.50 | $0.81 | $404 | $808 |
Every 10-cent change in diesel moves the surcharge by about 1.5 cents a mile under these assumptions. These are illustrative calculations; your contract terms decide your numbers.
Why base price and mpg matter
Two carriers can quote the same linehaul rate but very different total costs:
| Carrier | Base | MPG | Surcharge at $6.18 | Total on 1,000 miles with $2.50 linehaul |
|---|---|---|---|---|
| Carrier A | $1.25 | 6.5 | $0.76/mi | $3,258 |
| Carrier B | $2.00 | 6.0 | $0.70/mi | $3,197 |
| Carrier C | $1.00 | 5.5 | $0.94/mi | $3,442 |
Illustrative calculations. Always compare total cost, not linehaul alone.
LTL and parcel fuel surcharges
LTL carriers usually charge fuel as a percentage of linehaul charges, from a published table indexed to the weekly EIA diesel price. Because it’s a percentage, a general rate increase also raises the dollar value of the fuel surcharge.
Parcel carriers publish weekly fuel surcharge percentages for ground and air services, applied to transportation charges and some surcharges. Tables change periodically, and changes are often as significant as the annual rate increase.
What to put in carrier contracts
- Name the index. Specify the EIA series (national or regional) and the day it’s read.
- Fix the base and mpg for the contract term, and use the same assumptions for every carrier in a bid.
- Set the timing. State which week’s price applies to a shipment: pickup date or invoice date.
- Cap percentage surcharges for LTL and parcel, or negotiate a discount off the published table.
- Allow audits. Reserve the right to audit fuel charges and recover overbilling.
- Review quarterly. Agree to revisit the table if fuel moves outside a set range.
How to audit fuel surcharges
- Pull invoice-level fuel charges and miles.
- Recalculate the expected surcharge using the contract formula and the correct week’s EIA price.
- Flag variances above a threshold, such as 1%.
- Recover overcharges monthly; small per-load errors add up over thousands of loads.
Related reading
Questions procurement teams are asking
How is a truckload fuel surcharge calculated?
A common method subtracts a base diesel price from the current weekly EIA average diesel price and divides by an assumed fuel economy. With a $1.25 base and 6.5 miles per gallon, diesel at $6.18 gives a surcharge of about $0.76 per mile.
Which diesel price do fuel surcharges use?
Most U.S. contracts use the EIA's weekly retail on-highway diesel price, either the national average or a regional average, published on Mondays.
What is a fair base price for a fuel surcharge?
There is no single standard. What matters is that linehaul rates and the surcharge use consistent assumptions. A low base shifts more cost into the surcharge and should come with lower linehaul rates.
How do LTL fuel surcharges work?
Most LTL carriers publish a table that sets the surcharge as a percentage of linehaul charges, based on the weekly EIA diesel price. Contracts can cap the percentage or apply a different table.
How we wrote this guide
This guide draws on 2 sources, listed below, and on our own reporting. It was last reviewed on October 14, 2026 and is updated when rules or market conditions change. It is general guidance, not legal or financial advice. See our editorial standards.
