Diesel vs Gas Truck Calculator
Does the diesel option pay for itself? Pick your truck, how far you drive and how much you tow. Fuel prices come from the EIA every week, option prices from real window stickers.
Quick Answer: At the EIA U.S. average for the week of Nov 9, 2026 (diesel $6.127, regular gas $3.995, a $2.13 gap), diesel costs more per mile than gas in all five of our sample trucks, from a commuter who never tows to a fifth-wheel tower. That means the $11,400 to $12,995 heavy-duty diesel option does not pay for itself on fuel. Diesel only becomes cheaper to run once it falls to about $4.69 to $5.15 a gallon at today's gas price. Buy diesel when you tow near or past the gas engine's rating; that is a capability decision, not a money one.
Start from a typical owner
Your truck and driving
6.4L HEMI V8 vs 6.7L Cummins High Output
EIA U.S. average, week of Nov 9, 2026: regular $3.995, diesel $6.127.
Gas. Diesel costs more to run before you even pay for it.
At these prices diesel costs $1,186 more a year in fuel, DEF and maintenance, on top of the $13,370 option. You end $12,176 behind after 7 years.
Diesel vs gas, year 1 running cost
Costs $1,186 more
fuel, DEF and upkeep
Net when you sell, year 7
$12,176 behind
after $13,370 option
Diesel pays back in
Not in 15 years
Diesel price to tie gas per mile
$4.69
you pay $6.13; to also pay back by year 7: $4.02
Even towing every mile, diesel does not tie gas on running cost at these prices.
Diesel minus gas over 15 years
Includes the option price, any loan interest and the option value you would get back if you sold that year. Above the dashed line, diesel is ahead.
Official Ram window sticker: $12,495 on Big Horn, $12,995 on Tradesman and Black Express.
MPG: Towing MPG from TFL's Ram HD Cummins vs HEMI towing loop. Empty MPG borrowed from Car and Driver's Super Duty test; no matching Ram test. TFL Ram HD Cummins vs Hemi towing loop, Apr 2026, Car and Driver 2026 F-250 test
Tow ratings: gas 17,740 lb, diesel 20,000 lb. 2027 Ram 2500 maximum ratings. Equipment World, 2027 Ram HD
Fuel: EIA weekly retail prices, week of Nov 9, 2026. EIA Gasoline and Diesel Fuel Update
Five sample trucks at this week's fuel prices
EIA U.S. average, week of Nov 9, 2026: regular $3.995, diesel $6.127. 7 year ownership, cash purchase, 7% tax on the option.
| Owner | Year 1 diesel vs gas | Net at year 7 | Pays back | Diesel price to tie |
|---|---|---|---|---|
| Commuter HD 12,000 miles, never tows | -$848 | -$9,807 | No | $4.71 |
| Weekend tower 15,000 miles, 20% towing a 7,000 lb camper | -$1,186 | -$12,176 | No | $4.69 |
| Fifth wheel 18,000 miles, 40% towing a 14,000 lb fifth wheel | -$1,226 | -$12,457 | No | $5.15 |
| High-mileage worker 30,000 miles, 25% towing equipment | -$2,373 | -$20,483 | No | $4.73 |
| Half-ton diesel 15,000 miles in a Silverado 1500, 3.0L Duramax vs V8 | -$694 | -$4,860 | No | $5.06 |
Negative means diesel costs more. Fifth wheel towing MPG (7 vs 10) is an estimate for a heavy trailer; change it under More inputs.
How the math works
- Gallons a year for each engine = empty miles divided by empty MPG, plus towing miles divided by towing MPG.
- Year 1 running cost difference = gas fuel cost minus diesel fuel cost, DEF and extra diesel upkeep.
- Net in any year = running cost differences so far, minus the option price with tax and any loan interest, plus the share of the option you get back if you sold that year.
- Diesel price to tie = the diesel pump price where both trucks cost the same to run per year.
- Heavy-duty pickups have no EPA fuel economy label, so MPG comes from published road tests. Every source is linked.
What would change the answer
- Diesel prices falling back toward the gas price. In November 2024 diesel was only $0.47 a gallon over gas.
- Heavy towing, where gas MPG falls much harder than diesel MPG.
- Very high mileage with a lot of towing, which multiplies any per mile saving.
- A trailer near or over the gas engine's tow rating. Then it is not a money decision.
- Short trips. A modern diesel needs regular hot runs to clean its DPF. See our DPF and short trips guide.
Keep reading
FREQUENTLY ASKED QUESTIONS
Estimates only. Option prices are 2027 model year list prices; dealer discounts, trims and your real MPG change the result. 4x4 Playground is independent and sells no trucks or parts.