Diesel fuel price volatility can destroy carrier operating margins overnight if not properly offset by a structured Fuel Surcharge (FSC). In commercial freight contracting, fuel surcharges are pegged directly to the Energy Information Administration (EIA) / Department of Energy (DOE) National Average On-Highway Diesel Price Index, released every Monday. This guide explains how to calculate, audit, and negotiate fuel surcharge agreements.
1. The Standard Fuel Surcharge Formula
The standard freight industry fuel surcharge formula is based on three variables:
- Current DOE National Diesel Average: The weekly benchmark published every Monday afternoon (e.g. $4.10/gal).
- Base Fuel Peg: The baseline diesel price agreed in the contract before surcharges apply (standard industry peg: $1.25/gal or $1.50/gal).
- Fleet Average MPG Benchmark: Standardized Class 8 semi-truck fuel efficiency (typically set at 6.0 MPG or 6.5 MPG).
FSC Per Mile = (Current DOE Price - Base Fuel Peg) ÷ Base MPG Benchmark
Example: With diesel at $4.10, a $1.50 peg, and 6.5 MPG, the FSC per mile is: ($4.10 - $1.50) / 6.5 = $0.40 per mile. On a 1,000-mile haul, the carrier collects $400 in fuel surcharge on top of the linehaul rate.