Van fuel cost for each call: 4 diesel price checks

Van fuel cost for one service call equals the gallons used on that call multiplied by the price for each gallon.

Key takeaways

• Record the gallons used on the call.
• Match the price to the fuel product and date.
• Keep actual purchase prices separate from published estimates.

If you add fuel to the cost of each service call, you need a diesel price from somewhere, and a public source is an easy place to begin. This post covers 4 facts about one such source: the U.S. Energy Information Administration (EIA) weekly on-highway diesel fuel price estimates, as described on its methodology page .

The question behind this post is whether the fuel line in a call's cost figure can be defended. A published figure can help answer that, but only if it is read with its method, product, and sample in mind. The four facts are taken one at a time below, followed by a purchase check, a checklist, and a few ways to present the result.

Each fact describes that one series. Where a detail applies only to that series, the post says so. It should not be carried over to other prices, other agencies, or other fuel products without checking them separately.

Fuel cost for one call is the gallons used on that call multiplied by the price for each gallon. That is simple arithmetic, so the real work is getting both inputs right. The gallons should come from your own records, such as fuel card statements, pump logs, or trip mileage converted with your vehicle's fuel use. The price is the one you choose, either what you actually paid or a published estimate you decide to use as a planning figure. Make sure the gallons and the price use the same unit, and check the unit on the source page rather than assuming it.

The 4 facts below affect how far you can trust a published estimate as that price. None of them changes the arithmetic. They change what the number means.

The EIA's weekly estimates changed method on June 13, 2022. The agency explains: "On June 13, 2022, we implemented a new sample based on methodological changes made to improve the accuracy of our estimates of weekly on-highway diesel fuel prices." ( EIA methodology )

The same page adds: "As a result of these methodological changes, the published estimates for June 13, 2022, will not be directly comparable to those published in the June 6, 2022 release, which was based on the previous sample we used before our methodological updates." ( EIA methodology )

This matters if you line up a run of published prices, or your own cost for each call against them, across that week. Check the EIA methodology page before you read a gap between them as a change in diesel prices. A simple habit is to mark the June 2022 break on any chart or log, so that anyone reading it can see where the method changed.

The EIA's data represent ultra-low sulfur diesel (ULSD), which contains less than 15 parts of sulfur in a million. ( EIA methodology )

That sentence is a product description, and it matters when you match a published figure to your purchase records. Read the product name on each fuel purchase record and compare it with that description. The source says its data represent ULSD, so it does not speak to other grades or products that a fleet might buy. If your vans buy something other than ULSD, do not assume the published figure is the right price for that product. Look for a separate price for it, and label the figure with the product it covers.

The EIA says its "new diesel fuel outlet sample is a stratified systematic sample with a total size of 590 retail outlets." ( EIA methodology ) The sample was drawn from a frame of "approximately 73,000 service stations and 9,500 truck stops in the contiguous United States that were active in 2021." ( EIA methodology )

So the published price is an estimate built from a sample. It is not a count of every station in the country, and it is not a quote from the station where your van fills up. The frame described covers the contiguous United States, so the quote does not describe Alaska or Hawaii. If your fleet works in those areas, do not assume the figure matches local stations. Look for other price information for your area before you plan around it.

A sample can still be useful for planning, even when it does not match one station.

The EIA states that "the volumes are based on the most recently available annual sales volume data collected from Form EIA-888, On-Highway Diesel Fuel Price Survey Schedule B, only once when outlets are selected for a new sample." ( EIA methodology )

When you read a published figure, do not assume the volume data was refreshed that same week. The form name is useful if you want to look up the survey itself.

The source's terms carry specific meanings, so it helps to keep them in view when you read a published figure. The source uses "ultra-low sulfur diesel (ULSD)" for the product it reports, "sample" for the outlets selected for the survey, and "frame" for the list the sample was drawn from. A "retail outlet" in this context is a place that sells fuel, and the frame names service stations and truck stops as its examples.

The quote calls the outlet sample "stratified systematic." That is a sampling method. If you need that detail, read it from the methodology page directly rather than relying on a summary, including this one.

A fuel purchase record can be checked against the four facts before you use it in a call's cost figure. Start with the date of purchase, and find the published week it falls in. If the two releases on either side of June 13, 2022 are involved, keep the method change from Fact 1 in mind before you compare them.

Next, read the product name on the purchase record and compare it with the ULSD description from Fact 2. If the record shows a different product, the published figure is not the right comparison, and you need another price for that product. Then check the quantity. The gallons on the purchase record are the figure to use for the call, provided they match the vehicle and the job in your log.

Last, do not treat the published figure as the price on the purchase record. The purchase record shows what you paid at a particular outlet, while the published figure is an estimate built from the sample in Fact 3. Keep both numbers on the record, each with its label, so a reader can see the difference between them.

Fuel can be treated as a variable cost, which is a cost that moves as activity moves. The OpenStax managerial accounting chapter uses a t-shirt business to show this idea: "Figure 2.16 shows how the variable cost of ink behaves as the level of activity changes." ( OpenStax )

You can think about fuel the same way. If the fuel a van uses goes up when it drives more miles or makes more calls, then for that work, fuel is behaving like a variable cost. That is a reasoning step for your own books, not a rule from the source.

The same chapter notes that a fixed cost can be considered for each unit. ( OpenStax ) That is a different question from how a variable cost moves. Before you put fuel in a call's cost figure, decide which group it belongs to in your own records. Then keep that label consistent, so the same kind of cost is handled the same way every time.

Build the figure in this order: record the gallons, pick the price, check the four facts, then multiply. Skipping a step can leave a number meaning something other than what its label says.

1. Record the gallons used on each call from your own logs.
2. Pick the published price for the period, and write down its date and the product it describes.
3. If the period includes the June 6, 2022 and June 13, 2022 releases, check the method change before you compare the two.
4. Confirm that the product on your purchase records matches the ULSD description. If it does not, find a price for that product instead.
5. Note that the EIA sample introduced on June 13, 2022 contains 590 retail outlets; its estimate is not a local quote.
6. Multiply gallons by price, using the same unit for both, and label the result as an estimate.

The result is one input to your pricing, not a final cost. Keep the arithmetic visible so a reader can see the gallons, the price, and the date behind each figure. For the wider calculation, see service call expenses to add before you quote .

Illustrative example: Calculate one call's fuel cost

Record the gallons, price, product and price date alongside the result. These illustrative amounts are not a current diesel price or a measured van's fuel use.

A call's fuel cost figure is only as useful as the record behind it. Keep the same fields for each call so the figure can be checked later. Useful fields include the date, the job or customer, the vehicle, the gallons used, the price used, the source and its date, and whether the price was an actual purchase or a published estimate.

When your actual purchases differ from the published figure, keep both. Use your own purchase prices for what you paid, and use the published figure where you need a planning estimate. Recording both lets you see the gap later instead of hiding it. Review the record at an interval you set for yourself, and compare the logged gallons, prices, and sources against the facts in this post each time. A review like that catches a product mismatch or a method change before it reaches a quote. Revisit the record when a source changes its method or product description. The June 2022 change in Fact 1 shows that a method can change, so the record should show which method and which product each figure came from.

The EIA describes its weekly figures as estimates of weekly on-highway diesel fuel prices, so a published figure is not a purchase record. Watch for these mistakes:

• Using the published figure as the price your vans paid.
• Comparing the June 6, 2022 and June 13, 2022 releases without checking the method change.
• Assuming the figure describes a product other than ULSD.
• Assuming the 590 outlets are the stations you buy from.
• Treating a sample estimate as if it were a single station's price.

The first mistake is the easiest to make, because a published number looks precise. The source describes its figures as estimates, so a label that says "estimate" keeps the figure from being read as a purchase record. The second mistake is easy to miss in a log that spans June 2022, because the rows look alike even when the method behind them changed.

Each mistake comes from reading a published number as something the source does not say it is. Keeping the quotes in view is the simplest guard against that.

State where the call's fuel cost figure came from and that it is an estimate. When you share it with a bookkeeper, a manager, or a customer, name the source, give its date, and say which product it covers. A label such as "estimated fuel cost for this call, based on the logged gallons and the EIA weekly diesel estimate for a stated date" is clearer than a single number with no context.

If a reader asks about a difference between the June 6, 2022 and June 13, 2022 releases, explain that they are not directly comparable. Say that plainly, and link to the EIA methodology page rather than adding reasons the quotes do not give.

Also say when you last checked the figure. Diesel prices move, and a call's fuel cost figure built on an older price should say so. Plain wording helps more than precision that the inputs cannot support. A reader who knows the gallons, the price, and the date can judge the figure for themselves.

This post does not cover your local pump prices, prices outside the EIA series, or rules from other agencies or states. It also does not give a fuel cost for any particular call, because the gallons used on each call depend on your own records. The sources used here are the EIA methodology page and an OpenStax managerial accounting chapter. If you use other sources, check each one against its own page before you rely on it.

Choose one logged call, confirm its gallons and fuel product, and calculate its fuel cost with a dated price. Before saving a revised quote, review your price book amounts .

Which price should I use?

Use your actual purchase price to record spending, or a labelled published estimate for planning.

Can I assign a whole fuel purchase to one call?

Use only the gallons that your records match to that call. Check the vehicle and job in your log before calculating the cost.