2026 head-to-head · Full-Size Pickup
2026 GMC Sierra vs GMC Sierra Diesel
MPG, range and what each one really costs you to fuel, from official EPA ratings and recalculated with your own gas and electricity prices.
The 2026 GMC Sierra Diesel is the cheaper one to run. Driving 15,000 miles a year with $3.10/gal regular gas and $3.70/gal diesel fuel, it costs about $2,220 a year to fuel (25 MPG), versus $2,325 for the 2026 GMC Sierra (20 MPG). That's roughly $105 a year, or about $525 over five years.
Your numbers
Change these to match your driving and local prices. Every figure and chart on this page updates.
Fuel cost over 10 years
- GMC Sierra
- GMC Sierra Diesel
Side by side
| GMC Sierra | GMC Sierra Diesel | |
|---|---|---|
| $2,325 | Your annual fuel cost | $2,220 |
| 20 MPG | Combined efficiency | 25 MPG |
| 18 MPG | City | 23 MPG |
| 21 MPG | Highway | 28 MPG |
| 464 g/mi | Tailpipe CO₂ (g/mi) | 402 g/mi |
| 4/10 | EPA fuel economy score | 5/10 |
| 4/10 | EPA greenhouse gas score | 4/10 |
| Gas | Powertrain | Diesel |
| Regular gasoline | Fuel | Diesel |
| 2.7L 4-cyl turbo | Engine / motor | 3.0L 6-cyl turbo |
| 8-speed automatic | Transmission | 10-speed automatic |
| RWD | Drivetrain | RWD |
✓ marks the better value. EPA scores run 1–10 (10 is best). Volumes come from the EPA interior volume index and aren't published for every body style.
GMC Sierra vs GMC Sierra Diesel across model years
- GMC Sierra
- GMC Sierra Diesel
Annual fuel cost of the most efficient configuration of each model year, at your prices. Click a point to open that year.
How they differ
Among 21 2026 full-size pickups, the GMC Sierra ranks 17th and the GMC Sierra Diesel 15th for lowest fuel cost.
The powertrains differ: the GMC Sierra is a conventional gas model, while the GMC Sierra Diesel is a diesel.
Frequently asked questions
Which is more fuel-efficient, the 2026 GMC Sierra or the 2026 GMC Sierra Diesel?
Measured by cost to drive, the GMC Sierra Diesel. The GMC Sierra is rated 20 MPG combined and the GMC Sierra Diesel 25 MPG (EPA, most efficient configuration of each).
How much does it cost to fuel the 2026 GMC Sierra vs. the GMC Sierra Diesel per year?
At 15,000 miles a year with $3.10/gal regular gas and $3.70/gal diesel fuel, about $2,325 for the GMC Sierra and $2,220 for the GMC Sierra Diesel.
GMC Sierra vs GMC Sierra Diesel in other years
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