Surging Diesel Prices Threaten to Squeeze Consumers and Fuel Broader Inflation

Stanlow Petrol Refinery in Ellesmere Port, England, Oct. 2, 2026.

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While consumers are already grappling with elevated gasoline prices, another type of fuel—diesel—threatens to drive up costs on store shelves in a less visible yet highly impactful way, according to economists.

According to data from AAA, diesel prices have surged by 68% since the onset of the conflict in Iran, outpacing the increase in gasoline prices and highlighting the broader energy strain.

This surge in diesel costs threatens to ripple across the economy, raising prices for a wide range of goods—from food to everyday physical items—at a time when inflation remains stubbornly high.

“This represents another significant squeeze on consumers,” said Michael Reid, head of U.S. economics at the Royal Bank of Canada. “Lower- and middle-income households, which spend a larger proportion of their income on essential goods, will feel this pressure disproportionately.”

How much have diesel prices increased?

Average diesel prices climbed to $6.32 per gallon on Tuesday, up from $3.76 per gallon on February 27—the day before the U.S. and Israel initiated strikes on Iran, according to AAA data.

September marked a historic milestone, as national average diesel prices surpassed the $6-per-gallon threshold for the first time on record.

In response to the escalating crisis, the Group of Seven nations—France, Canada, Germany, Italy, Japan, the United Kingdom, and the United States—agreed on Friday to a “substantial release” of diesel reserves. The Trump administration had reportedly pressured European allies to release diesel stocks as an alternative to the U.S. implementing an export ban aimed at lowering domestic fuel prices.

Meanwhile, President Donald Trump signed an executive order on Monday temporarily allowing the broader use of cheaper red-dyed diesel—typically restricted to agricultural operations—in an effort to alleviate record-high fuel costs.

Economists attribute the primary driver of the price surge to the conflict in Iran. The war has severely curtailed oil supply flows through the Middle East and damaged critical refining infrastructure in the region, disrupting the production of diesel, gasoline, and jet fuel.

Compounding these supply shocks, the ongoing war in Ukraine has also exerted upward pressure on diesel prices. Kyiv’s strikes on Russian refineries have prompted Moscow to ban diesel exports, further tightening global supply.

What is impacted by diesel prices?

As of Tuesday, average gasoline prices stood at $4.37 per gallon, representing a 47% increase from $2.98 per gallon on February 27, according to AAA.

While gasoline price fluctuations are highly visible to consumers at the pump, the economic impact of rising diesel prices operates largely under the radar, despite its widespread reach.

“Gas is direct—it comes straight out of your pocket at the pump,” explained Mark Zandi, chief economist at Moody’s. “Diesel, on the other hand, is indirect, embedded in the cost of everything we buy.”

Diesel serves as the lifeblood of global logistics, powering trucks, trains, and cargo ships that transport goods to stores. Beyond transportation, it is a vital input in agriculture, manufacturing, and residential or industrial heating, according to a Goldman Sachs Research note published on September 21.

Economists note that businesses inevitably pass these elevated diesel costs onto consumers through higher retail prices.

“Essentially, anything transported by truck will see its price affected by higher diesel costs—ranging from everyday groceries to packages delivered to your doorstep by carriers like UPS or Amazon,” Zandi explained.

Zandi summarized the situation with a common industry adage: “Cars run on gas, but the economy runs on diesel.”

Freight costs are currently accelerating at a rate comparable to the post-Covid economic reopening, with many of the transport methods involved relying heavily on diesel, according to Reid.

Because trade routes are largely fixed and businesses cannot easily reduce transit distances to save on fuel, higher diesel input costs will cascade along the supply chain, ultimately being passed down to the consumer.

How much might prices increase?

Diesel fuel stations at a Shell gas station in Los Angeles, California, on Sept. 28, 2026.

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Zandi explained that these price impacts take time to filter through to consumers, with the full effects likely taking anywhere from six months to a year to fully pass through the market.

As a general rule of thumb, for every $1 increase in the cost of a gallon of diesel, consumers can expect overall inflation to rise by approximately 0.1 percentage points, assuming these higher prices are sustained.

With diesel prices up roughly $2.50 per gallon since the start of the Iran war, Zandi noted that this alone typically adds about 0.25 percentage points to overall inflation, as measured by the personal consumption expenditures (PCE) price index.

The PCE index is the Federal Reserve’s preferred gauge for measuring inflation. While the central bank aims to maintain an annual inflation rate around 2% over the long term, the index was running at a 3.4% annual pace as of August.

Reid described the upcoming inflationary pressure as a gradual “drip” rather than a sudden shock: “It may be a slow climb over the next few months where goods prices gradually move higher, and consumers won’t feel it as a one-time jump, but rather a persistent, incremental ticking up.”

In a September 21 research note, Goldman Sachs stated that persistently higher diesel prices are expected to boost food prices cumulatively by 0.2 to 0.4 percentage points over the coming months. Diesel accounts for roughly 5% to 10% of average input costs across crops.

“We see risks that food prices could increase further if diesel prices remain elevated, as farmers purchase fuel disproportionately during the fall harvest season and often buy fuel in the winter for storage,” Goldman Sachs noted.

Goldman Sachs forecasts that diesel prices will remain elevated through 2027.

Reid suggested that the G7’s announcement regarding a strategic release of diesel reserves is unlikely to significantly alleviate current high prices.

“The longer elevated oil and energy prices persist due to the conflict in Iran, the greater the risk that these costs bleed meaningfully into the broader consumer goods market,” Reid warned.

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