Which DOE Week Applies to Your Fuel Surcharge?

The DOE week that applies to your fuel surcharge is whichever week your contract names, and nothing else. Usually that is the weekly index published before the ship date, effective for loads tendered the following week. If your carrier used a later week instead, the surcharge on that invoice is wrong, and on a rising diesel market it is wrong in the carrier’s favor every single time.

This is the most checkable field on a freight invoice and almost nobody checks it. The linehaul is easy to verify because there is one number on the rate confirmation to match. Accessorials take argument. Detention takes evidence, which is why disputing a detention charge with no in and out times on the POD is a document exercise rather than a math one. But the fuel surcharge is pure arithmetic against a public government number, and the only input anyone gets wrong is the date.

We flag this constantly. A Dallas to Memphis truckload billed at 31.5 percent when the correct week gives 28.9 percent is a $118 error on one load. Multiply by a lane you run every week and it stops being a rounding difference.

This post assumes you already know the shape of the calculation. If you do not, read how to calculate a truckload fuel surcharge from the DOE index first and come back. Everything below is about the date, not the formula.

How the DOE weekly index cadence actually works

The number everyone calls “the DOE index” is produced by the Energy Information Administration through the On-Highway Diesel Fuel Price Survey. The mechanics matter, because they explain why a week of lag exists at all.

EIA collects prices on Form EIA-888 from 590 retail diesel outlets across the contiguous United States. The price captured is the cash self-serve pump price including taxes, as of 8:00 a.m. local time on Monday. The results are published the next day, on Tuesday, and move to Wednesday when Monday falls on a government holiday. The release is broken out by PADD region plus a national average and a separate California figure.

Two consequences follow directly:

The number is stamped with a Monday, not a Tuesday. EIA labels the observation by the survey date. When a contract says “the DOE index for the week of March 9,” it means the survey taken Monday March 9, which nobody could actually see until Tuesday March 10. A carrier billing a Monday pickup cannot possibly have used that Monday’s number, because it did not exist yet.

There is exactly one number per week and it does not change. Unlike a spot market, the index is a discrete weekly step. Once published, a week’s price is fixed. So there is never ambiguity about what a given week’s number is, only about which week you were supposed to use. That is what makes this auditable to the penny.

For scale, the U.S. average on-highway diesel price for the week ending July 27, 2026 was $5.313 per gallon, with PADD-level figures ranging from $5.087 on the Gulf Coast to $6.670 in California. Those regional spreads are a separate audit issue. This post is only about time.

The three conventions your contract might use, and why they disagree

Almost every truckload and LTL fuel program in the country uses one of three effective-date conventions. They are all defensible. They are not interchangeable, and in a moving market they produce three different invoices for the same load.

Here is the same shipment under all three. Pickup Thursday March 12, delivery Wednesday March 18. The weekday alignment below is real; the diesel prices are illustrative.

Walk the calendar and it is obvious why. The March 9 survey publishes Tuesday March 10. A load picking up Thursday March 12 already has that number available, so a pickup-date convention grabs it. But a convention with a Monday effective date holds the March 9 number until Monday March 16, which means the March 12 pickup is still governed by the week ending March 2. And a delivery-date convention on Wednesday March 18 reaches forward to the March 16 survey, published Tuesday March 17.

One load. Three legitimate readings. Three different weeks of diesel.

The first convention is the most common in negotiated truckload contracts, and it is also the one carriers most often fail to implement, because it requires holding a stale number for up to six extra days after a fresher one is sitting on the EIA website.

Which field on the invoice and which clause in the rate con

You need two documents open.

On the invoice, find the effective index. A compliant freight bill has to show the exact rates assessed and the nature and amount of each charge under 49 CFR 373.103. In practice, carriers express the fuel basis one of three ways:

• A cents-per-mile figure on the fuel line, sometimes with the underlying diesel price in a memo field.
• A percentage on the fuel line, typical in LTL, which maps back to a bracket in the carrier’s published table.
• A separate “FSC basis” or “fuel week” field, often labeled with a date. This is the good case: the date is right there and you can check it in ten seconds.

If the invoice shows only a dollar amount with no basis, ask for the basis in writing. You are entitled to know the nature and amount of each charge, and a carrier that cannot tell you which week it used has already lost the argument.

On the rate confirmation or contract, find the effective-date clause. It sits in the fuel surcharge section, usually one sentence after the peg price and the index name. You are looking for four things:

1. The index: national average, a specific PADD, or California.
2. The peg or base price where the surcharge starts.
3. The MPG divisor, for per-mile programs.
4. The effective-date rule. The words “preceding,” “in effect on,” “week of shipment,” “date of pickup,” and “date of delivery” all carry different consequences.

If the rate con is silent on effective date, the carrier’s rules tariff almost certainly fills the gap, and the rules tariff is written by the carrier. A silent rate con is not a win for you.

Watch also for a mismatch between the ship date on the BOL and the pickup date on the rate confirmation. When those differ, and the load picked up a day late, a pickup-date convention can legitimately move to the next index week. That is a correct bill, and it is why you check the BOL rather than just the invoice header.

A worked example: what one week of lag costs

Same shipment as above. The contract says the index published on the Monday preceding the week of shipment, effective the following Monday. That is convention one, the week ending March 2. The carrier billed off the week ending March 16, which is the delivery-date convention. Prices below are illustrative.

Program terms, also illustrative: peg $1.25 per gallon, 6.0 MPG divisor, 452-mile lane.

The per-mile surcharge is the amount diesel exceeds the peg, divided by the MPG assumption.

Correct, week ending March 2: ($5.146 - $1.25) / 6.0 = $0.6493 per mile $0.6493 x 452 miles = $293.50

As billed, week ending March 16: ($5.238 - $1.25) / 6.0 = $0.6647 per mile $0.6647 x 452 miles = $300.43

Difference: $6.93 on one load.

Seven dollars. That is the number that makes everyone stop auditing this field, and it is exactly why the error survives.

Now run the lane. Fifteen loads a week, 52 weeks, is 780 loads:

$6.93 x 780 = $5,405 a year, on one lane, from one wrong date.

Nothing about that requires an unusual diesel move. In a volatile stretch the per-load number is several times larger.

What makes this worth your time is that the error is systematic. Once a carrier’s billing system is configured to the wrong convention, it applies that convention to every load, forever, until somebody tells it not to. Fixing the configuration once fixes every future invoice.

Why the error almost always runs the same direction

If wrong-week errors were random, they would cancel out and you could ignore them. They do not cancel out, for a structural reason.

Every one of the three conventions above selects a later week as you move from “published preceding Monday” to “in effect on delivery.” A carrier that skips its contractual holding period, or that defaults to a system-wide delivery-date rule, is always reaching for a fresher index week than the contract allows.

On a rising diesel market, a fresher week is a higher price. Higher price, higher surcharge, higher invoice.

On a falling market the same misconfiguration works against the carrier, and something interesting happens: those errors get found. A carrier’s own revenue assurance notices undercollection quickly. Nobody on the carrier side is incentivized to notice overcollection. So the errors that survive to appear on your invoice are disproportionately the ones that favor the carrier, regardless of what the market did.

This is also why “we spot-checked a few and they were fine” is not a reliable finding. If you spot-checked during a flat or falling stretch, the convention error was invisible. It reappears the moment diesel climbs.

Auditing a batch of invoices for this one error

You do not need software to run this once. You need a spreadsheet and about ninety minutes for a hundred invoices. Whether it is worth paying someone to run it every week instead is a separate question, and one that turns on how freight audit providers price the work.

1. Pull the rule first, not the invoices. Read the effective-date clause in each carrier contract or rate con template and write it down verbatim in one column. If you have six carriers you likely have three or four different conventions. Getting this wrong at step one invalidates everything downstream.

2. Download the weekly index series once. The weekly U.S. on-highway diesel retail price series gives you every week’s number in one table. Pull the same series your contract names, national or the specific PADD, for the whole period you are auditing. Paste it into a lookup tab.

3. Build four columns per invoice. Ship date from the BOL, applicable index week per your contract rule, index price for that week, and recomputed surcharge. A date lookup does the third column automatically.

4. Compare recomputed against billed, and sort by direction. Do not sort by dollar size. Sort by whether the variance is positive or negative. A batch where 90 percent of variances favor the carrier is a configuration error, not noise. A batch where variances scatter in both directions by a few cents is rounding, and you should leave it alone.

5. Isolate the pattern before you write anything. If every variance on one carrier is exactly one index week late or early, say that. “Your system is applying the delivery-date index where our contract specifies the Monday preceding shipment” is a fixable statement. “Invoice 48213 seems high” is not.

6. Watch your billing clocks. Under 49 U.S.C. 13710, a shipper must contest a bill within 180 days of receiving it to preserve the right to challenge. If you are auditing a year of history, some of it may already be out of reach. The other deadlines that bound this work are collected in our reference to every freight billing deadline that can cost you money.

7. File it as an overcharge claim, in writing. An overcharge claim should come with the freight bill and the rate or tariff authority relied on, per 49 CFR 378.4. Once it is written, the processing carrier has to pay, decline, or settle within 60 days under 49 CFR 378.8. Attach your recomputation table and the EIA page. This is one of the rare disputes where the evidence is a public government number and there is nothing for the carrier to dispute except the contract reading.

If you are the shipper

Your leverage is the contract, and your fix is a configuration change, not a claim. Run the audit, find the pattern, then take it to the carrier as a billing setup issue rather than a fight over one invoice. Ask for the correction to be applied prospectively and for the identified historical variances to be credited on the next invoice. Most carriers will do this without escalation because the fix costs them nothing to implement and the alternative is you auditing every bill forever.

If you are the broker

You have the same error on both sides of the load, and they may not use the same convention. If your carrier rate con specifies pickup-date index and your customer contract specifies the preceding-Monday index, that spread is margin leakage on every load in a rising market, and it is invisible in your load-level P&L because both numbers look correct in isolation. Reconcile the two clauses against each other before you reconcile any invoice, using the same field-by-field method you would apply to any rate confirmation that disagrees with the carrier invoice. Where they differ, either align them at renewal or price the gap in.

The short version

• The applicable DOE week is whatever the contract says, and the three common conventions produce three different numbers on the same load.
• EIA surveys prices as of Monday and publishes the following day, so a Monday pickup can never be billed off that Monday’s number.
• Find the effective-date clause in the rate con first, then the fuel basis field on the invoice, then the ship date on the BOL.
• Recompute against the published weekly series. The math is exact and public.
• Sort variances by direction, not size. One-direction variance is a configuration error worth fixing at the carrier level.
• Contest within 180 days, file the overcharge claim in writing, and expect a decision inside 60 days.

Sources

• EIA, On-Highway Diesel Fuel Price Survey methodology
• EIA, Gasoline and Diesel Fuel Update (weekly retail prices by PADD)
• EIA, Weekly U.S. No 2 Diesel Retail Prices (on-highway series)
• 49 CFR 373.103, Form of freight bill
• 49 U.S.C. 13710, Information and records
• 49 CFR 378.4, Documentation of claims
• 49 CFR 378.8, Disposition of claims