Fuel Surcharge Calculator: Peg-and-Step and MPG Methods

Enter your peg and this week’s diesel price. You get the surcharge per mile under a peg-and-step schedule and under an mpg formula, the fuel economy your contract quietly assumes, and whether it covers your own truck.

How to use it

Start with the two prices. The base, also called the peg, comes from your contract or the broker’s fuel schedule: it is the diesel price at which the surcharge is zero. The current price is the weekly retail on-highway diesel figure from the U.S. Energy Information Administration. EIA publishes a national average and regional series; use the one your contract names, because they can be far apart.

Then fill in the method your contract uses. A peg-and-step schedule says something like “1 cent per mile for every 6 cents above $2.50”: the step is $0.06 and the increment is 1 cent. An mpg formula says “(current price − base) ÷ 6”. Fill in both if you want to compare them. The optional fields test the result against your truck’s real fuel economy, put a dollar figure on one load, and express the surcharge as a percentage of linehaul.

Worked example

Illustrative contract terms, not market terms: peg $2.50, step $0.06, increment 1 cent per mile, priced against the EIA US average of $6.199 a gallon for the week of October 5, 2026.

Price above the peg: $6.199 − $2.50 = $3.699.
Steps: $3.699 ÷ $0.06 = 61.65, so 61 whole steps.
Surcharge: 61 × $0.01 = $0.610 per mile.
Mpg method at 6 mpg: $3.699 ÷ 6 = $0.617 per mile.

If your truck really does 6.5 mpg loaded, your extra fuel cost above the peg is $3.699 ÷ 6.5 = $0.569 a mile, so the step schedule pays about 4 cents a mile more than the extra fuel. On a 500-mile load the step schedule pays 500 × $0.61 = $305.00. Against a $2.00 linehaul that is 30.5 percent.

Why the two methods are the same thing

A step schedule is an mpg formula written as a table. Divide the step by the increment and you get the fuel economy it assumes: $0.06 ÷ $0.01 = 6 mpg. A 5-cent step paying 1 cent assumes 5 mpg, which pays the carrier more for the same diesel price. The calculator shows this implied mpg for whatever step and increment you enter.

The only difference is rounding. Counting whole steps drops the leftover fraction, so a step schedule pays up to one increment per mile less than the equivalent mpg formula. Switch the step count to “pro rata” and the two methods give the same answer: 61.65 steps × 1 cent = $0.6165, exactly $3.699 ÷ 6.

Common mistakes

Using the wrong series. A contract tied to the national average does not pay the California or West Coast price, even if that is where you buy fuel.
Using a stale price. EIA collects prices as of Monday and normally publishes on Tuesday. Check which week, and how often, your contract resets.
Judging the increment without the peg. A generous increment on a high peg can pay less than a modest one on a low peg.
Assuming the formula’s mpg is yours. Enter your real loaded fuel economy in the optional field and see the gap.
Forgetting empty miles. Surcharge is usually paid on loaded miles; fuel is burned on all of them. Price the gap into your linehaul, as covered in our fuel surcharge guide.

Questions

Where do I find the current diesel price for a fuel surcharge?

Most US contracts use the weekly retail on-highway diesel price from the U.S. Energy Information Administration. Prices are collected as of Monday and normally published on Tuesday; in a week with a federal holiday the release can move to Wednesday. Use the national or regional series your contract names.

How do I turn a peg-and-step table into an mpg formula?

Divide the step by the increment, both in dollars. A schedule paying 1 cent per mile for every 6 cents of price movement assumes 6 miles per gallon, because $0.06 ÷ $0.01 = 6. The two give the same result except that step tables usually count whole steps only.

Is a percentage-of-linehaul surcharge the same as cents per mile?

No. A percentage surcharge pays more on a high linehaul rate and less on a cheap one, even though the truck burns the same fuel. Enter a linehaul rate in the calculator to see what percentage your cents-per-mile figure represents, and compare that with the percentage you are offered.

Nothing leaves your browser

The calculation runs entirely on your device. Your figures are not sent anywhere and we cannot see them. If your browser allows it they are saved locally so the form is still filled in when you come back — the Clear all fields button removes that copy.

How a fuel surcharge works — the peg, the step, and the questions to ask before you sign.
Break-even rate calculator — the rate you need once fuel and every other cost is in.
Cost per mile calculator — what your fuel line really costs per mile.

Fuel Surcharge Calculator