Diesel Prices in 2026: What Fuel Actually Costs Per Mile

The U.S. Energy Information Administration put the national average on-highway diesel price at $5.257 a gallon for the week ending August 10, 2026. At 6.5 MPG that is $0.809 a mile — about $105,140 of fuel a year on 130,000 miles. Fuelling on the Gulf Coast puts it at $0.776 a mile; fuelling in California puts it at $1.018.

That is the whole answer, and everything below is the arithmetic behind it: what fuel costs at your MPG, what it costs in each EIA region, how to check the fuel surcharge a broker is paying you against it, and the four changes that actually move your annual fuel bill.

Every figure on this page derives from the EIA reading above and from stated assumptions (6.5 MPG, 2,500 miles a week, 130,000 miles a year). Change the pump price and every number here changes with it — which is the point. Diesel is a weekly number, not a standing fact, and this page carries the week it was read.

About 30% right now, and you can check the arithmetic. ATRI's 2026 operational costs update puts the industry-average marginal cost of operating a truck at $2.336 a mile for 2025, of which $1.854 is everything other than fuel. Substitute today's fuel line — $5.257 at 6.5 MPG, or $0.809 a mile — and the total becomes $2.663 a mile, with fuel at 30.4% of it.

Set that against the revenue side. DAT's national dry van spot average was $3.00 a mile in June 2026, when spot passed contract for the first time since February 2022. A $3.00 load covers $0.809 of fuel and ATRI's $1.854 of everything else with $0.337 a mile left over — about $843 across 2,500 loaded miles in a week.

Read that as a worked illustration on industry averages, not as what your truck will earn. ATRI's non-fuel line already includes driver compensation, so for an owner-operator that $0.337 sits on top of the wage line rather than instead of it — and your insurance, truck payment and maintenance will not match the industry average. Both inputs are dated observations: the ATRI figure describes 2025 and the diesel figure describes one week of 2026. For where the rate side goes next, see our freight rate recovery analysis and the market indicators worth watching.

One structural note: fuel is roughly 30% of cost per mile, but it is close to 100% of the cost that changes week to week. Your truck payment does not move when Brent does. That is why a working fuel surcharge matters more than its share of the total suggests.

California ran $6.618 against a national $5.257 for the week ending August 10, 2026 — a premium of $1.361 a gallon. The common explanation is state fuel tax, and the numbers do not support it.

California's diesel excise tax is $0.482 a gallon effective 1 July 2026 (CDTFA). Pennsylvania charges $0.741 a gallon on undyed diesel — $0.259 a gallon more than California — and yet the Central Atlantic region that contains Pennsylvania sat at $5.535, $1.083 below California in the same week. Excise tax is not what makes California expensive.

What is left is the fuel itself and the programs attached to it: California requires its own diesel specification, which limits which refineries can supply the state, and layers state carbon programs and sales tax on top of the pump price. We are not putting a cents-per-gallon figure on each of those components, because we could not source one — the number that is sourced is the EIA pump price, and the $1.361 premium is what you price against.

The federal rate, for comparison: IRS Publication 510 puts the federal excise tax on diesel and kerosene at $0.244 a gallon. That is identical in every state, so all state-to-state variation comes from state rates, blend rules and distribution — and all of it flows through your quarterly fuel tax return. Our IFTA filing guide covers how the tax you paid at the pump is reconciled against the miles you ran in each jurisdiction — which is the reason where you fuel and where you drive are two separate questions.

The honest answer is that we can source the diesel half of the comparison and not the electric half. The diesel side is fixed by this page: $5.257 a gallon at 6.5 MPG is $0.809 a mile, $105,140 a year on 130,000 miles. That is the number any electric proposal has to beat, and it is the number to check any vendor's comparison against — if a total-cost pitch assumes diesel below $0.809 a mile, it is using an old pump price.

The electric side depends on purchase price, charging cost, residual value, payload lost to battery weight and charging time, and we could not verify figures for those to a primary source in a form worth publishing. An earlier version of this page carried several — a registrations share, a national charger count, a fleet size — with no source attached to any of them. They have been removed rather than restated, and this section will get numbers again when it can get sourced ones.

What is structurally true and does not need a statistic: battery-electric Class 8 works today where the route returns to a base you control and is short enough to charge overnight. Long-haul, irregular-route owner-operators are not that case. Our EV trucks guide for owner-operators goes into the total-cost framework in detail.

One correction worth stating plainly, because this page previously got it wrong: the federal Clean Vehicle Credit under IRC 30D — the credit this article used to link to — is a light-duty consumer credit with an MSRP cap far below a Class 8 tractor, and the DOE records it as expired on 30 September 2025. It never applied to a Class 8 purchase and it no longer exists. Do not build a purchase case on it.

Nobody knows, including us, and 2026 is the evidence: the consensus forecast entering the year was $3.50 and the actual series has averaged $4.80 and touched $5.64. The one directional signal worth carrying is the EIA's own: its August 2026 Short-Term Energy Outlook has Brent at $87 a barrel for 2026 and back to $69 for 2027 — which is a forecast, and forecasts are what this section is warning you about.

So build for volatility instead of for a level. Three things follow from that, and none of them require knowing where diesel goes.

Keep the surcharge mechanism. Whenever diesel is high, brokers have a reason to push for all-in rates; the moment you accept one, your fuel exposure stops adjusting. Insist on a line-item FSC written against the current DOE weekly price with a stated base price and base MPG, on every rate confirmation. It is worth $87,902 a year at today's price on a 6.0 base — and the point of it is that the figure moves on its own.

Spend on MPG, not on hedging. Efficiency is the only fuel position you can take that pays in both directions. Getting from 6.5 to 7.0 MPG is $7,510 a year at $5.257 — and it is still worth $4,943 a year if diesel returns to its 2026 low of $3.46.

Know your own cost per mile. Every number on this page is a national or regional average, and averages are for orientation, not for pricing. Your MPG, your lanes and your fixed costs decide what a load is worth to you. Put your own figures into the cost per mile calculator and the fuel cost calculator, then compare the result against the region rows above rather than against the national headline.