2026 head-to-head · Full-Size Pickup
2026 GMC Sierra Diesel vs Jeep Gladiator
MPG, range and what each one really costs you to fuel, from official EPA ratings and recalculated with your own gas and electricity prices.
4WD · 3.6L 6-cyl · 8-speed automatic · 19 MPG
The 2026 GMC Sierra Diesel is the cheaper one to run. Driving 15,000 miles a year with $3.70/gal diesel fuel and $3.10/gal regular gas, it costs about $2,220 a year to fuel (25 MPG), versus $2,447 for the 2026 Jeep Gladiator (19 MPG). That's roughly $227 a year, or about $1,137 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 Diesel
- Jeep Gladiator
Side by side
| GMC Sierra Diesel | Jeep Gladiator | |
|---|---|---|
| $2,220 | Your annual fuel cost | $2,447 |
| 25 MPG | Combined efficiency | 19 MPG |
| 23 MPG | City | 17 MPG |
| 28 MPG | Highway | 22 MPG |
| 402 g/mi | Tailpipe CO₂ (g/mi) | 469 g/mi |
| 5/10 | EPA fuel economy score | 4/10 |
| 4/10 | EPA greenhouse gas score | 4/10 |
| Diesel | Powertrain | Gas |
| Diesel | Fuel | Regular gasoline |
| 3.0L 6-cyl turbo | Engine / motor | 3.6L 6-cyl |
| 10-speed automatic | Transmission | 8-speed automatic |
| RWD | Drivetrain | 4WD |
✓ 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 Diesel vs Jeep Gladiator across model years
- GMC Sierra Diesel
- Jeep Gladiator
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 Diesel ranks 15th and the Jeep Gladiator 21st for lowest fuel cost.
The powertrains differ: the GMC Sierra Diesel is a diesel, while the Jeep Gladiator is a conventional gas model.
Frequently asked questions
Which is more fuel-efficient, the 2026 GMC Sierra Diesel or the 2026 Jeep Gladiator?
Measured by cost to drive, the GMC Sierra Diesel. The GMC Sierra Diesel is rated 25 MPG combined and the Jeep Gladiator 19 MPG (EPA, most efficient configuration of each).
How much does it cost to fuel the 2026 GMC Sierra Diesel vs. the Jeep Gladiator per year?
At 15,000 miles a year with $3.70/gal diesel fuel and $3.10/gal regular gas, about $2,220 for the GMC Sierra Diesel and $2,447 for the Jeep Gladiator.
GMC Sierra Diesel vs Jeep Gladiator in other years
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