Fuel Surcharge (FSC) Calculator
Work out the fuel surcharge you should be charging — the way it is actually set: from the DOE diesel index against your base (peg) price, not a guessed per-mile number.
How a fuel surcharge works
A fuel surcharge (FSC) is the part of the freight rate that moves with the price of diesel. The base rate is agreed on the understanding that it already covers fuel up to a set price — the peg, or base price. When diesel rises above that peg, the surcharge adds the difference back per mile, so the carrier is not paying the shipper’s fuel spike out of the base rate. When diesel falls back to the peg, the surcharge falls with it, for the same reason: that fuel money is already inside the rate.
Most surcharge tables are tied to the U.S. Department of Energy (DOE/EIA) weekly diesel index — the national average retail diesel price published every Monday. Carriers, brokers and shippers check the new index each week and apply the table written into their contract or tariff. The fuel surcharge calculator above works the same way: enter this week’s diesel price, your peg and your truck’s fuel economy, and it shows the surcharge per mile and the total for the load.
The three ways to calculate a fuel surcharge
1. The index formula (per mile). Surcharge per mile = (current diesel price − peg price) ÷ MPG. Worked with the example figures: diesel at $4.00, a $1.25 peg and 6.5 MPG gives (4.00 − 1.25) ÷ 6.5 = $0.42 per mile, so 1,000 loaded miles carry $423.08 of surcharge. This is how most real FSC programmes are set, because it tracks the actual cost of the fuel burned.
2. A percentage of the linehaul. The surcharge is a percentage of the freight charge, taken from a scale table: as the diesel price climbs through set bands, the percentage climbs with it. The calculator shows an example scale and fills the percentage in from the diesel price you enter, but the field stays editable — your contract’s table always governs, never an example.
3. A flat rate per mile. A simple agreed number of cents per mile. It is easy to audit, but it does not move with the index, so it quietly under-recovers when diesel spikes and over-recovers when diesel falls, until somebody renegotiates it.
What is a peg price — and why the surcharge can be $0
The peg (base price) is the diesel price already built into the base rate. A peg of $1.25 a gallon has been a long-standing figure in many tariffs, which is why the calculator starts there. If the weekly index is at or below your peg, the index formula returns $0 — and that is not a mistake. It means the fuel for this load is already paid for inside the base rate, and adding a surcharge on top would be charging for the same diesel twice. If your real-world fuel economy is worse than the figure in your agreement, that gap — not the surcharge table — is where the money is leaking.
Which miles does a fuel surcharge cover?
Normally, loaded (revenue) miles only. Deadhead miles are usually excluded unless the agreement says otherwise in writing — one reason your empty-mile share matters, and worth checking with the Blended Rate & Deadhead Calculator. A surcharge is also revenue, not profit: compare it against what the load actually costs you per mile with the Per-Mile Profit Calculator. And keep it separate in your head from fuel tax — the surcharge is money in, while IFTA is a tax settlement on the fuel you burned in each state, estimated with the IFTA Fuel Tax Estimator.
Frequently asked questions
What is a fuel surcharge in trucking?
It is an adjustable part of the freight rate that rises and falls with the price of diesel, calculated from a published index against a base (peg) price written into the rate agreement. It exists so a rate quoted when diesel was cheap does not bankrupt the carrier when diesel spikes — and so the shipper is not overpaying when diesel falls.
How do I calculate a fuel surcharge per mile?
Subtract the peg price from the current diesel price and divide by your truck’s miles per gallon: (diesel − peg) ÷ MPG. At $4.00 diesel, a $1.25 peg and 6.5 MPG, that is $0.42 per mile. Multiply by the loaded miles for the total surcharge on the load — $423.08 on 1,000 loaded miles.
Where do I find the diesel price for the index?
From the U.S. Energy Information Administration (EIA), which publishes the national average retail diesel price every Monday (Tuesday after a federal holiday). Most contracts name that index and the day it is read, so check your agreement for which series — national or a regional PADD average — your table uses.
Does a fuel surcharge apply to deadhead miles?
Usually not. Standard surcharge programmes pay on loaded miles only, and the empty miles to reach the load are the carrier’s cost unless the contract says otherwise. If a broker offers a surcharge on all miles, that is a genuinely better term — get it in writing on the rate confirmation.