- U.S. on-highway diesel prices rose from $3.477 to $5.348 per gallon between the first week of January and the first week of August 2026, a 53.8% increase, the largest January-to-August rise in the 32 years of weekly EIA data since 1995.
- Diesel peaked at $5.643 on Apr 6 (62.3% above January), fell 18.9% to $4.578 by Jul 6, then rose again into August.
- Distillate fuel oil inventories fell 17.1% between the first week of January and the end of July, from 129.3 million to 107.2 million barrels.
- For a combination truck driving the FHWA average of 60,205 miles a year at 6.91 MPG, the change from the January price to the August price adds about $16,297 a year in fuel cost.
These are national averages; your actual fuel cost depends on your specific vehicle and location.
Calculate Your Exact Cost01 The 2026 Diesel Spike: What Happened
The national average price of on-highway diesel fuel opened 2026 at $3.477 per gallon in the first week of January. By the first week of August it stood at $5.348, an increase of 53.8% in seven months.
U.S. Energy Information Administration, Weekly U.S. No 2 Diesel Retail Prices, week of Jan. 5, 2026 and week of Aug. 3, 2026Diesel rose faster and further than gasoline did over the same period. Prices climbed sharply starting in the first week of March ($3.897, then $4.859 a week later), reaching a peak of $5.643 on Apr 6, 62.3% above the January level and about a month before gasoline's May peak. Diesel then retreated through late spring and early summer, falling 18.9% to a low of $4.578 on Jul 6, before climbing again through July into early August.
U.S. Energy Information Administration, Weekly U.S. No 2 Diesel Retail Prices, weekly series, January–August 2026The EIA's July 2026 Short-Term Energy Outlook ties the oil price rise to a conflict that began on February 28 and effectively closed the Strait of Hormuz until a June 18 agreement, and it notes that refiners worked to maximize jet fuel production and maintain distillate production in response to high global demand. The rise in U.S. diesel prices began in the same week of March as the gasoline rise.
U.S. Energy Information Administration, Short-Term Energy Outlook, July 2026 (Overview, Global Oil Markets and Refining). See why gas prices spiked in 2026 for the same context on the gasoline side.02 How Unusual Is This?
Since 1995, the median January-to-August change in diesel prices has been +5.4%. 2026's 53.8% increase is the largest January-to-August rise in the entire 32-year series, ahead of 2022's 42.2% and 2008's 33.4%.
Calculated from U.S. Energy Information Administration, Weekly U.S. No 2 Diesel Retail Prices, 1995–2026. Comparison uses the first weekly price in January and in August of each year.| Rank | Year | Jan-to-Aug Change |
|---|---|---|
| 1 | 2026 | +53.8% |
| 2 | 2022 | +42.2% |
| 3 | 2008 | +33.4% |
| 4 | 2021 | +27.5% |
| 5 | 2006 | +25.1% |
| 6 | 2005 | +20.0% |
| 7 | 1999 | +18.8% |
| 8 | 2004 | +18.4% |
| 9 | 2011 | +18.2% |
| 10 | 2007 | +12.3% |
03 What Drove It: Distillate Inventories
U.S. distillate fuel oil inventories (the category that includes on-highway diesel) fell from 129.3 million barrels in the first week of January 2026 to 107.2 million barrels by the end of July, a decline of 17.1%. Stocks reached their 2026 low of 100.8 million barrels (78.0% of the January level) in the week of May 22, while the diesel price low after the April peak came on Jul 6. The data show the two moving over the same months; they do not measure how quickly one responds to the other.
U.S. Energy Information Administration, Weekly U.S. Ending Stocks of Distillate Fuel Oil. Week of Jan. 2 to week of Jul. 31, 2026 (the most recent data available at time of writing).04 The Cost to Trucking and Freight
The FHWA's Highway Statistics data puts the average combination truck (a tractor-trailer, the standard long-haul freight vehicle) at 60,205 miles traveled per year, averaging 6.91 miles per gallon, which works out to about 8,710 gallons of diesel consumed annually.
FHWA, Highway Statistics 2022, Table VM-1: Annual Vehicle Distance Traveled and Related Data. Combination trucks: average miles traveled 60,205; average miles traveled per gallon 6.91; average fuel consumed per vehicle 8,710 gallons.At January's $3.477 per gallon, fueling that truck for a year cost approximately $30,285. At August's $5.348 per gallon, the same truck costs approximately $46,581, an increase of about $16,297 per truck per year, before any other operating costs.
Calculated: 8,710 gallons × $3.477/gal = $30,285; 8,710 gallons × $5.348/gal = $46,581; difference = $16,297. Uses the FHWA VM-1 combination-truck fuel consumption figure above.Curious how fuel price changes affect your own vehicle's annual cost?
Use the Calculator05 How This Compares to Gasoline
Gasoline prices also spiked in 2026, rising 52.9% from January to August, the second-largest such increase since 1994. Diesel's 53.8% increase was larger, and is the largest January-to-August increase in diesel's own 32-year series. Both fuels show the same broad pattern: a sharp climb starting in March, a partial retreat in the summer and a renewed climb into August.
Calculated from EIA weekly all-grades gasoline and No. 2 diesel retail prices. See Why Gas Prices Spiked in 2026 for the gasoline-side data.06 Data Sources
- U.S. Energy Information Administration: Weekly U.S. On-Highway Diesel Fuel Prices, 1995–2026. eia.gov
- U.S. Energy Information Administration: Weekly U.S. Ending Stocks of Crude Oil and Petroleum Products (Distillate Fuel Oil). eia.gov
- U.S. Energy Information Administration: Short-Term Energy Outlook, July 2026. eia.gov/outlooks/steo
- Federal Highway Administration: Highway Statistics 2022, Table VM-1. fhwa.dot.gov