Diesel vs gasoline price: today's state-by-state spread
Today the US average diesel-over-regular spread is about $1.53 per gallon (regular $4.07, diesel $5.60, both US national figures from the same EIA survey week [EIA · 31 Aug 2026]). The gap widens in CARB-spec states like California and Washington and narrows along the Gulf Coast where refining capacity for both fuels is densest.
Why diesel is usually above regular
Diesel and gasoline are both distillates of the same crude barrel but they compete for the same refinery output. Three structural drivers explain the spread:
- Year-round demand. Trucking and rail freight buy diesel every week of the year. Gasoline is more seasonal.
- ULSD specification cost. Ultra-low-sulfur diesel (15 ppm) requires hydroprocessing.
- Heating-oil correlation. Northeast No. 2 distillate demand crowds out diesel from October through March.
When did diesel first overtake gasoline?
The 2004-2005 transition to ULSD (mandated 1 June 2006 for on-highway) cemented a structural diesel premium. Before then, diesel was generally cheaper than regular. EIA Today In Energy has tracked the inversion. [EIA · 31 Aug 2026]
2026 outlook
EIA's Short-Term Energy Outlook expects retail gasoline to average lower in 2026 than in 2025 (about 6 percent, roughly 20 cents a gallon, as crude eases), while on-highway diesel keeps trading above regular because distillate refining capacity stays tight. The current per-gallon gap is shown in the spread figure above. [EIA · 31 Aug 2026]
Related
All diesel · cheapest diesel on I-80 · heating-oil cross-reference · refining margin