If you have ever wondered why 8,000 gallons on the meter is not 8,000 gallons on the invoice, temperature is the first place to look. Fuel temperature correction restates a measured volume as the volume it would occupy at 60°F. The glossary entry on gross vs net gallons covers the definitions.
How do you correct fuel volume to 60°F?
Multiply the gross gallons by a volume correction factor for the product at the temperature it was measured. The Texas Comptroller’s motor fuels audit manual defines net gallons as “gross gallons corrected or adjusted to a temperature of 60 degrees Fahrenheit.” The factor is below 1 for fuel warmer than 60°F and above 1 for fuel colder than 60°F.
The steps:
- Read the gross gallons from the meter or delivery ticket.
- Read the product temperature recorded at loading.
- Look up the factor for that product and temperature.
- Multiply: net gallons = gross gallons x factor.
- Multiply net gallons by the price per gallon, if the sale is on net.
Where do the correction factors come from?
They come from petroleum measurement tables. The Texas manual prints one table for gasoline at a gravity of 62, showing net gallons per 10,000 gross gallons. It also says “There are several different tables that result in slightly different figures,” so treat any single table as approximate. For a real invoice, use the table your contract or state names.
| Temperature | Gross gallons | Net gallons | Factor |
|---|---|---|---|
| 40°F | 10,000 | 10,138 | 1.0138 |
| 50°F | 10,000 | 10,069 | 1.0069 |
| 60°F | 10,000 | 10,000 | 1.0000 |
| 70°F | 10,000 | 9,930 | 0.9930 |
| 80°F | 10,000 | 9,861 | 0.9861 |
| 90°F | 10,000 | 9,790 | 0.9790 |
The net column is from the Texas manual’s table; the factor column is that figure divided by 10,000. The manual gives no figures for diesel. It says only that “Diesel fuel does not expand or contract as much as gasoline,” so for diesel use your own contract’s table.
The table moves in 10-degree steps, so the worked example below uses temperatures that sit on it. A real ticket records the actual temperature, such as 83°F, and the factor is looked up or calculated for that exact reading. Do not interpolate by hand on a disputed load; ask the party that issued the ticket which table and factor it used and request the working.
What does the correction look like on a warm day and a cold day?
Say you take a gasoline load of 8,000 gross gallons. The price below, $2.50 a gallon, is illustrative and not a market quote. The factors are the Texas table’s values at 90°F and 40°F.
| Line | Warm day (90°F) | Cold day (40°F) |
|---|---|---|
| Gross gallons | 8,000 | 8,000 |
| Factor | 0.9790 | 1.0138 |
| Net gallons (gross x factor) | 7,832 | 8,110.4 |
| Gallons difference (net - gross) | -168 | +110.4 |
| Gross value at $2.50 | $20,000 | $20,000 |
| Net value at $2.50 | $19,580 | $20,276 |
| Dollar difference | -$420 | +$276 |
Same meter reading, same truck, different weather. On the warm day, billing on net takes $420 off the invoice compared with billing on gross. On the cold day, billing on net adds $276.
The gallons did not vanish. Warm gasoline takes up more room, so a gross count overstates how much product you got. Cold gasoline takes up less, so a gross count understates it.
Which number should your invoice use?
Whichever your contract says, and the ticket should show enough to check it. Terminals commonly load and bill on net, while many end-customer deliveries are billed on gross, as the glossary entry explains. A buyer on a gross-basis delivery pays for warm-weather expansion in the summer. A supplier that buys net and sells gross gets the opposite: it is short product in the cold.
When a quantity looks off, check these on the ticket:
- Whether it shows gross, net, or both.
- The temperature at loading.
- The product and the table or factor used.
- Whether the purchase and the sale are on the same basis.
For other reasons the delivered quantity moves after the order, see why your fuel invoice changed after delivery. A load is also limited by the trailer, covered in how many gallons a fuel tanker holds.
How does temperature correction change a quote comparison?
It does when one quote is on net and another on gross. Fuel quoted at the same price per gallon is not the same price if one basis delivers fewer billable gallons. In the table above, the gap on one 8,000-gallon load was $420 on a warm day. A biodiesel blend can hide the same kind of gap, depending on whether RINs come with the fuel. Ask which basis each quote uses before you rank them, and see how to compare bulk fuel quotes for the rest of the checklist.
How Energy Connect handles it
The basis of sale, the temperature table, and who absorbs the gross-to-net difference are terms between the buyer and the supplier, so agree them in the contract. On Energy Connect, the bill of lading and delivery documents are attached to the load, so you can check each ticket against those terms.