Diesel prices in California
$8.25 a gallon this week — 20.7¢ up on last week. That is the California average from the EIA's weekly survey, published for the week of 21 September 2026.
Where this number comes from
California is the only state the EIA publishes on its own, so this is a genuine state-level figure. It is a retail average including taxes, surveyed every Monday and published on Tuesday.
Where it was a year ago
The California average was $4.98 in the week of 2025-09-29. It is $8.25 now — $3.27 more a gallon, or $490 on every 150-gallon fill.
What it costs to run
At $8.25 a gallon, by fuel economy:
| MPG | Per mile | 500-mile run | Per 100,000 miles |
|---|---|---|---|
| 5.5 mpg | 149.9¢ | $749.64 | $149,927 |
| 6.0 mpg | 137.4¢ | $687.17 | $137,433 |
| 6.5 mpg | 126.9¢ | $634.31 | $126,862 |
| 7.0 mpg | 117.8¢ | $589.00 | $117,800 |
| 7.5 mpg | 109.9¢ | $549.73 | $109,947 |
The spread between 5.5 and 7.5 mpg is 40.0¢ a mile — worth more over a year than almost any fuel-buying strategy. What moves the number is here.
Against the states next door
Neighbours inside the same EIA region carry the same published average, so the differences below are region boundaries showing up on a map — which is exactly where a fuel stop is worth planning.
| State | EIA region | Per gallon | vs California |
|---|---|---|---|
| Arizona | West Coast (ex. CA) | $6.79 | $1.46 cheaper |
| Nevada | West Coast (ex. CA) | $6.79 | $1.46 cheaper |
| Oregon | West Coast (ex. CA) | $6.79 | $1.46 cheaper |
The cheapest state bordering California is Arizona at $6.79 — $1.46 a gallon less, or $218.25 on a 150-gallon fill.
Price this into an actual load
An average is a planning figure, not a trip cost. The calculator takes a real lane, your truck's mpg and the regions the route actually crosses, and works out the fuel against the rate you were offered — with the empty miles, the tolls and the lumper in the same number.
For where to buy it, the California truck stop directory lists every mapped stop in the state by town.
Questions
What is the diesel price in California today?
$8.25 a gallon, from the U.S. Energy Information Administration's weekly retail on-highway survey for the week of 21 September 2026. California is the one state the EIA publishes on its own.
Does the EIA publish a California-only diesel price?
Yes — California is the single state with its own published series, because its fuel specification and taxes make it behave differently from the rest of the West Coast.
How often does this update?
Weekly. The EIA surveys on Monday and publishes on Tuesday afternoon, so the figure changes once a week. This page reads the latest figure every time it loads, rather than showing whatever was true when it was written.
Is this the price at the pump?
No. It is a retail average across the region, including taxes. An individual truck stop can be 30¢ either side of it, and cash, fuel-card and negotiated prices differ again. Use it for planning a trip's cost, not for predicting a specific pump.
What does a tank of diesel cost in California?
About $1,236.90 for 150 gallons at this week's average — and a 500-mile run at 6.5 mpg burns roughly $634.31 of it.