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Fuel Surcharge Calculator

Work the per-mile fuel surcharge from the EIA weekly diesel average, your peg price and your contract MPG, with the trip total and break-even peg.

Independently built and reviewed by the FleetOpsClub research team. Published October 8, 2026. Last verified October 8, 2026.

Calculate Your Fuel Surcharge







What a fuel surcharge is

A fuel surcharge is the part of a freight rate that moves with the price of diesel. The linehaul rate is negotiated against an assumed fuel price — the peg, or base price — and the surcharge covers the difference between that peg and what diesel actually costs this week. Set the peg, the index and the MPG assumption and you have fixed the surcharge for the life of the contract; those three terms are the whole negotiation.

The formula, and what we checked it against

Surcharge Per Mile = (Current Diesel Price − Peg Price) ÷ MPG

Checked on 8 October 2026 against two sources rather than repeated from other calculators. The index is the U.S. Energy Information Administration’s weekly series U.S. On-Highway Diesel Fuel Prices, which includes all taxes; the week ending 10/05/26 printed $6.199 per gallon, released 6 October 2026. The per-mile mechanic is the one the Owner-Operator Independent Drivers Association publishes in its own surcharge tool: price difference divided by MPG, worked as $5.25 − $2.50 = $2.75, then $2.75 ÷ 6.0 ≈ $0.46 per mile. Both are linked below.

Where this formula does not apply

Less-than-truckload carriers do not use it. Old Dominion’s published fuel tariff, ODFL 128-CC, effective 9 April 2025, applies a percentage increase to the linehaul charge, banded by the same EIA index in cents per gallon. Its table runs from 12.72% in the 100–115¢ band to 41.32% in the 505–510¢ band, and its Note D adds 0.5% for every further 5¢. There is no MPG term anywhere in it. The step between bands is not constant either — 0.30% per 5¢ low in the table, 0.50% per 5¢ high in it — so the schedule is a negotiated document, not something you can re-derive. The same tariff reads the index every Tuesday (Wednesday if Monday is a federal holiday) and adjusts every Wednesday on the EIA figure effective the previous Monday, which puts the rate you pay about nine days behind the pump. If you ship LTL, read your carrier’s tariff; this page will not reproduce it.

Worked example

Current diesel: $6.199/gal (EIA, week ending 10/05/26)
Peg: $1.25/gal — a legacy peg, still common in older contracts
Contract MPG: 6.0
Trip: 500 miles

Spread: $6.199 − $1.25 = $4.949/gal
Surcharge per mile: $4.949 ÷ 6.0 = $0.8248 (82.48¢/mile)
Trip surcharge: 500 × $0.8248 = $412.42

Move the peg to $3.00 and the same week bills $0.5332/mile, or $266.58 — $145.84 less on one 500-mile load. That is what the peg is worth.

Why the MPG assumption decides who wins

The surcharge and your real incremental fuel cost are the same expression divided by two different MPG numbers: the contract’s assumption and your truck’s actual figure. The peg cancels out of that comparison. It decides whether a surcharge is owed; the MPG assumption alone decides whether the surcharge over- or under-recovers what the fuel cost you. A contract written at 6.0 MPG against a truck that really runs 6.8 over-recovers by about 13%, every mile, in every week diesel is above the peg — $0.0970 a mile at a $1.25 peg and this week’s $6.199 diesel. Enter your actual MPG above and the calculator will size that gap in dollars.

Auditing a surcharge you have already been billed

Enter the per-mile surcharge from the invoice in the last field. Because the formula has one unknown once the index and MPG are fixed, it inverts: the calculator reports the peg that billed rate implies. If that implied peg is not the peg in your rate confirmation, either the index date is different from the one you assumed or the rate is wrong. Check the date first — it is usually the date.

Sources

All three read at source on 8 October 2026.

U.S. Energy Information Administration, Gasoline and Diesel Fuel Update — U.S. On-Highway Diesel Fuel Prices.  eia.gov/petroleum/gasdiesel. Week ending 10/05/26: $6.199/gal, released 6 October 2026.

Old Dominion Freight Line, Inc. (MC-107478), Fuel Increase Master Tariff ODFL 128-CC, effective 9 April 2025, Items 1–2 and Note D.  odfl.com (PDF).

Owner-Operator Independent Drivers Association, Fuel Surcharge Calculator.  ooida.com.

Related calculators

Work the surcharge back into a rate with the cost per mile calculator, check the MPG assumption against your real fleet figure with the fleet MPG calculator, or size total diesel spend with the fleet fuel cost calculator.

Frequently asked questions

Quick answers to the questions buyers usually ask once the category, software, or rollout details start getting more specific.

A

For truckload and owner-operator freight: (current diesel price per gallon minus the base or peg price) divided by the assumed miles per gallon, which gives a surcharge per mile. OOIDA publishes this same arithmetic in its own surcharge tool. Less-than-truckload carriers use something different — a percentage added to the linehaul charge, banded by diesel price, with no MPG term at all.

A

The EIA weekly series U.S. On-Highway Diesel Fuel Prices, at eia.gov/petroleum/gasdiesel. It is published weekly, includes all taxes, and is the index carrier tariffs name. Old Dominion's tariff ODFL 128-CC points at that exact page. Regional PADD averages exist on the same page if your contract names one.

A

There is no normal — the peg is a negotiated term, and the spread between an old peg and a current one is worth more than most rate negotiations. Legacy contracts often still carry pegs around $1.20 to $1.25 a gallon, which at today's diesel means almost the whole price is surcharged. Read the number off your rate confirmation rather than assuming one.

A

Usually not, but that is a contract term and not a rule. Most agreements floor the surcharge at zero rather than crediting the shipper. This calculator floors it at zero and also shows you the unfloored figure, so you can see what the formula would have produced and check what your contract actually says.

A

Almost always the index date. Carrier tariffs lag deliberately: ODFL 128-CC reads the EIA index on Tuesday and adjusts the following Wednesday using the figure effective the previous Monday, so the rate you are billed reflects diesel from about nine days earlier. Enter the billed per-mile rate in the last field and the calculator will tell you which peg it implies, which usually isolates whether the problem is the date or the rate.

A

It is whatever the contract says, and that is rarely your real figure — 6.0 is a common assumption. The gap matters: the peg cancels out of any comparison between the surcharge and your actual incremental fuel cost, so the MPG assumption is the only term that decides whether the surcharge over- or under-recovers. Enter both numbers above to see the gap in dollars per mile.

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