Diesel vs Gasoline: Price, Power and Efficiency
Diesel currently averages $6.18 per gallon against $4.33 for regular gasoline — a $1.85 premium (EIA, week of 2026-10-12). The gap is structural: cleaner-fuel rules, higher tax, and industrial demand. Here's the full comparison.
Side by Side
| Gasoline | Diesel | |
|---|---|---|
| US average price (this week) | 4.33 | 6.18 |
| Energy per gallon | ≈120,000 Btu | ≈137,000 Btu (+12%) |
| Engine ignition | Spark | Compression |
| Typical efficiency | Baseline | 20–35% better MPG |
| Federal tax | 18.4¢ | 24.4¢ |
| Futures benchmark | RBOB (NYMEX RB) | Heating Oil (NYMEX HO) |
| Winter behavior | Cheaper winter blend | Competes with heating oil — spread widens |
Price history for both fuels: gasoline by year · diesel by year. Current state-level prices: gas · diesel.
Wholesale diesel premium over gasoline: Where It Stands
Daily closes through Oct 19, 2026| Measure | Value | Context |
|---|---|---|
| Latest | $1.595 $/gal | −$0.069 on the day |
| Average, last 252 trading days | $0.728 | latest is above it by $0.867 |
| Highest in that window | $1.797 | Sep 15, 2026 |
| Lowest in that window | $0.106 | Jun 22, 2026 |
| Percentile | 95% | higher than 95% of the past 252 closes |
| A year earlier | $0.362 | change +$1.233 |
ULSD futures (NYMEX HO) minus RBOB gasoline futures, in dollars per gallon. The retail premium by year back to 1994 is on diesel price history. Computed on the dates both legs have a close, from this site's two-year daily history (from Oct 21, 2024). Descriptive statistics, not a forecast.
Wholesale diesel premium over gasoline by Month, Last 12 Months
| Month | Average | High | Low | Month-end |
|---|---|---|---|---|
| Oct 2026 TO DATE | $1.471 | $1.684 | $1.189 | $1.595 |
| Sep 2026 | $1.502 | $1.797 | $1.165 | $1.519 |
| Aug 2026 | $1.039 | $1.217 | $0.867 | $1.058 |
| Jul 2026 | $0.662 | $0.972 | $0.265 | $0.900 |
| Jun 2026 | $0.383 | $0.716 | $0.106 | $0.303 |
| May 2026 | $0.398 | $0.495 | $0.300 | $0.410 |
| Apr 2026 | $0.664 | $1.172 | $0.366 | $0.366 |
| Mar 2026 | $0.954 | $1.322 | $0.529 | $0.851 |
| Feb 2026 | $0.538 | $0.716 | $0.432 | $0.593 |
| Jan 2026 | $0.520 | $0.813 | $0.354 | $0.813 |
| Dec 2025 | $0.452 | $0.529 | $0.410 | $0.416 |
| Nov 2025 | $0.542 | $0.704 | $0.437 | $0.437 |
Calendar-month statistics of the daily values; the current month is partial. Live prices behind it: oil price charts.
Diesel vs Gas FAQ
How much more expensive is diesel than gasoline right now?
Diesel averages $6.18 per gallon versus $4.33 for regular gasoline (EIA, week of 2026-10-12) — a gap of $1.85. The spread widens in winter, when diesel competes with heating oil for the same refinery output.
How big is the wholesale gap between diesel and gasoline?
ULSD futures are $1.595 a gallon above RBOB gasoline futures at the Oct 19 close, against an average of $0.728 over the past 252 trading days (range $0.106 to $1.797). The wholesale gap is the starting point for the retail gap, which also includes the 6-cent difference in federal tax.
Why is diesel more expensive than gas?
Three structural reasons: US diesel must be ultra-low-sulfur (costlier to refine), federal tax is 6 cents higher (24.4¢ vs 18.4¢), and diesel faces relentless demand from trucking, farming, industry — and, in winter, home heating. Before 2005 diesel was usually the cheaper fuel; the sulfur rules and global demand flipped it.
Is a diesel engine more efficient than gasoline?
Yes — typically 20–35% better fuel economy. Diesel fuel carries about 12% more energy per gallon, and compression-ignition engines convert it more efficiently, especially under load. That's why trucking is diesel: at highway load a diesel semi does work no gasoline engine could do economically.
Why do diesel prices spike in winter?
Diesel and heating oil are essentially the same middle-distillate product, so a cold Northeast winter puts trucks and furnaces in competition for the same barrels. Distillate inventories heading into winter (published in the weekly EIA report) are the number to watch.