US Average Diesel Price Tops $6 a Gallon for the First Time Ever as Iran War Disrupts Fuel Supplies

The national average price of diesel fuel in the United States crossed $6 a gallon for the first time on record, according to GasBuddy, which tracks retail fuel prices in real time. The milestone follows a rapid run-up driven by global supply disruptions tied to a six-month conflict involving Iran, which has severely curtailed shipping through the Strait of Hormuz, and Ukrainian strikes on Russian refineries that have further strained fuel exports.

The $6 threshold was breached on September 10, 2026, just days after diesel had already set a series of fresh records. The Energy Information Administration reported that the national on-highway diesel average for the week ending September 7 had jumped 36.8 cents to $5.967 per gallon, itself surpassing the previous nominal weekly high of $5.810 set in June 2022. GasBuddy's real-time tracking, which updates more frequently than EIA weekly data, crossed the $6 mark shortly after. Patrick De Haan, head of petroleum analysis at GasBuddy, has said 2026 is on track to be the most expensive year for diesel on record.

Prices vary sharply by region. California diesel is approaching $8 a gallon, with some cities averaging nearly $8.50, a level De Haan described as "apocalyptic" and one that creates practical problems even for gas-station software not designed to display prices that high. Truckers are already feeling severe pain: one operator told reporters that fuel had cost him close to $45,000 for a 10,000-gallon fill this year, compared with roughly $25,000 the same fill cost in 2025.

Because diesel powers most of the country's freight and delivery network, the record price is expected to ripple quickly through consumer costs. Economists note that businesses have largely held off passing higher diesel costs to consumers so far, but that buffer is narrowing. Food, lumber, and other goods shipped by truck face higher transportation costs at a time when diesel's seasonal demand typically rises further into the fall.