Diesel 5 min read · updated Nov 9, 2026
Why diesel costs more than gasoline
A higher federal tax, a tighter global market and stricter fuel specs. The gap is not fixed.
Latest gap: diesel is $2.132 a gallon above regular gasoline (U.S. averages, Nov 9, 2026).
Diesel has not always cost more than gasoline, but it usually does. Four reasons explain most of the gap.
- Tax. Federal excise tax is 24.4¢ a gallon on diesel against 18.4¢ on gasoline, and many states also tax diesel at a higher rate.
- Global demand. Diesel and its close relatives (heating oil, jet fuel, marine gasoil) are traded worldwide. A shortage in Europe or a refinery outage in Asia can lift U.S. diesel; gasoline is a more regional market.
- Ultra-low sulfur. On-highway diesel must contain less than 15 parts per million of sulfur, which takes extra refining.
- Winter. Heating oil competes for the same barrels in the Northeast each winter, while gasoline demand eases.
The gap swings. It narrowed in years when distillate stocks were plentiful and widened sharply when they were tight. Track it weekly on the analytics page.
Does diesel's efficiency make up for it?
A gallon of diesel holds about 13% more energy than a gallon of gasoline, and diesel engines are often more efficient under load. Our diesel vs. gas calculator compares annual fuel cost with your own mileage and fuel economy.