What is a fuel surcharge?

A fuel surcharge (FSC) is an extra charge carriers add to the base freight rate to recover volatile diesel costs. It is usually published as a percentage tied to a national average diesel price index, updated weekly or monthly.

How is the percentage surcharge calculated?

Multiply the base line-haul rate by the published FSC percentage. A 1200 base rate with a 28.5 percent surcharge adds 342, for a total of 1542. Most LTL carriers post a current FSC percent that you apply this way.

How does the diesel peg table work?

Carriers set a peg price below which no surcharge applies. For every fixed increment the average diesel price rises above the peg, a set number of percentage points is added. For example, every 6 cents above 1.25 might add 0.5 percent.

Where do I find the diesel price index?

In the US, carriers reference the EIA national average on-highway diesel price, published every Monday. Many FSC schedules lag a week, so use the index date your carrier's tariff specifies when verifying an invoice.

Why verify the surcharge myself?

Fuel surcharges are a common source of overbilling because the percentage moves weekly and is applied to a base that varies by lane. Recomputing it from the published index lets you catch errors and budget accurately.

Freight Fuel Surcharge Calculator

Fuel surcharges move every week and ride on top of every freight invoice, which makes them an easy place for billing errors to hide. This calculator works both ways: apply a published surcharge percentage to a base rate, or build the percentage up from a diesel peg and step schedule.

How it works

The simple method multiplies the base rate by the published percentage:

surcharge = base rate × (FSC% / 100)
total     = base rate + surcharge

The peg method derives the percentage from how far the current diesel price sits above a peg, in fixed steps:

over    = max(0, dieselPrice − pegPrice)
steps   = floor(over / increment)
FSC%    = steps × stepPercent
surcharge = lineHaul × (FSC% / 100)

If you give trip miles and fuel economy instead of a line-haul amount, the tool estimates the extra fuel cost over the peg across the whole trip.

Example and tips

A 1200 line-haul rate with a 28.5 percent published surcharge adds 342, for a 1542 total. Under a peg schedule with a 1.25 peg, 6-cent increments, and 0.5 percent per step, an average diesel price of 4.10 sits 2.85 above the peg — that is 47 steps, or a 23.5 percent surcharge. Always confirm which diesel index date your carrier’s tariff uses, since most schedules lag the published price by a week, and recompute surcharges on disputed invoices before paying.