Fuel Surcharge Calculator
Calculate a trucking fuel surcharge per mile and per load from the current diesel price, the contract base price and truck MPG, plus its share of linehaul.
Most truckload contracts pass fuel costs through with a surcharge that rises as diesel climbs above an agreed base price. The standard formula divides the difference between the current price and the base by the truck's fuel economy, giving cents per mile. Use this to check a carrier invoice, quote a load, or see how much a price move changes your costs.
How to use this tool
- Enter the current diesel price — normally the DOE/EIA weekly average your contract names.
- Enter the base (peg) price from the contract and the MPG it assumes.
- Enter the loaded miles, and optionally the linehaul rate per mile.
- Read the surcharge per mile, the trip total and the percentage of linehaul.
Formula
FSC per mile = max(0, (current price − base price) ÷ MPG)
Trip surcharge = FSC per mile × miles
Because the base price is subtracted first, the surcharge only covers fuel cost above the level already built into the linehaul rate. The calculator floors negative surcharges at zero and uses the unrounded per-mile result for trip cost. Contract step tables may differ.
Example
Diesel at $3.75, a $1.25 base and 6 MPG: (3.75 − 1.25) ÷ 6 = $0.4167 a mile, displayed as $0.42. Multiplying the unrounded rate by 1,000 miles gives $416.67; rounding first would charge $420. With a $2.25 linehaul it adds 18.52%, for an all-in rate of about $2.67 a mile.
Frequently asked questions
Which diesel price should I use?
Whatever the contract specifies — most use the U.S. Energy Information Administration weekly on-highway diesel average, national or for a region, published on the EIA schedule; holidays can shift release dates.
Why do some contracts use a step table instead?
A step table has discrete price bands and its own rounding rules. Matching MPG alone does not reproduce every tariff table.
How do LTL fuel surcharges differ?
LTL carriers usually charge a percentage of the linehaul that moves with the diesel index, rather than cents per mile. Use the percentage from the carrier's published table for LTL.
Sources
Last updated: 2026-10-30