Fuel Economy Compared: Diesel vs. Gas Trucks in 2025

If you’re shopping for a truck in 2025, choosing between Diesel vs. Gas Trucks in 2025 is a major decision that hinges on fuel economy, performance, and cost.

Both powertrains have unique strengths, but fuel efficiency often sways buyers looking to save money while meeting their driving demands.

Let’s dive into how 2025 diesel trucks and gas-powered trucks compare in fuel economy, real-world use, and what it means for your wallet and lifestyle.

Diesel vs. Gas Trucks: Comparison Table

Feature	Diesel Trucks	Gas Trucks
Fuel Economy (MPG)	18-33 MPG (e.g., Chevy Silverado 1500 Diesel: 23 city/33 hwy)	16-42 MPG (e.g., Ford Maverick Hybrid: 42 city/33 hwy)
Best Use Case	Heavy towing, long-distance driving, high mileage (>30,000 miles/year)	City driving, light hauling, lower mileage
Towing Efficiency	Better MPG retention under heavy loads	Significant MPG drop when towing
Upfront Cost	$5,000-$10,000 more (e.g., Silverado 2500HD Diesel)	Lower (e.g., Silverado 2500HD Gas: ~$51,600 base)
Fuel Cost	Higher (~14¢/gal more); savings with high mileage	Lower; cheaper for low-mileage drivers
Maintenance	Costlier (DEF, particulate filters)	Cheaper; simpler parts, wider mechanic expertise
Engine Longevity	Longer (up to 500,000+ miles)	Shorter lifespan
Resale Value	Higher due to durability and demand	Lower compared to diesel
Environmental Impact	Less CO2/mile, more NOx/particulates 2025 emission standards	More CO2, fewer pollutants

Why Fuel Economy Matters in Trucks

Trucks are built for tough tasks like towing, hauling, and navigating rugged terrain.

With fuel prices unpredictable and environmental concerns rising, getting better miles per gallon (MPG) is crucial for many drivers.

Whether you’re a contractor transporting heavy equipment, a weekend adventurer towing a camper, or need a reliable daily driver, fuel economy affects your operating costs and how often you’re refueling.

Diesel and gas trucks approach efficiency differently, and understanding their advantages helps you make the right choice.

Diesel Trucks: Power Meets Efficiency

Diesel engines are renowned for torque and durability, but they also excel in fuel economy, particularly for demanding tasks. Here’s why:

• Higher Energy Density: Diesel fuel contains 10-15% more energy per gallon than gasoline, delivering more power with less fuel. This leads to better MPG, especially on highways or when towing heavy loads.
• Real-World MPG: In 2025, models like the GMC Sierra 1500 Diesel achieve up to 23 MPG city and 29 MPG highway. Heavy-duty options, such as the Chevy Silverado 2500HD with a 6.6L Duramax diesel, hit around 18 MPG city and 21 MPG highway. Light-duty diesels, like the Chevy Silverado 1500 with the 3.0L LZ0 turbodiesel, can reach an impressive 23 MPG city and 33 MPG highway.
• Towing Efficiency: Diesel trucks maintain better fuel economy under load. When towing heavy trailers, a diesel’s MPG drops less than a gas truck’s, thanks to superior torque and efficient combustion.
• Longevity Bonus: Diesel engines often last longer—some exceeding 500,000 miles with proper care—spreading fuel savings over a longer vehicle life.

However, diesel has downsides. Diesel fuel is often 14 cents per gallon more expensive than gasoline, and cold weather can cause fuel gelling, requiring additives.

Stricter emission standards mean diesel trucks need diesel exhaust fluid (DEF) and particulate filters, which increase maintenance costs.

Gas Trucks: Affordable and Versatile

Gas trucks remain popular for their affordability and versatility, especially for lighter duties. Here’s how they perform:

• MPG Performance: Gas trucks have improved with turbocharged engines, hybrid systems, and advanced transmissions. The 2025 Ford Maverick Hybrid leads with 42 MPG city and 33 MPG highway, while non-hybrid models like the Ford Ranger achieve 21 MPG city and 26 MPG highway. Full-size gas trucks, such as the Chevy Silverado 2500 with a 6.6L V8, average 16-17 MPG in mixed driving.
• Light-Duty Efficiency: For city driving or light hauling, gas trucks often outperform diesels due to simpler designs and better adaptation to stop-and-go traffic.
• Lower Fuel Costs: Gasoline is typically cheaper and more widely available, making refueling more convenient and cost-effective, especially for low-mileage drivers.
• Hybrid Options: Hybrids like the Ford F-150 2.7L EcoBoost combine gas engines with electric motors, delivering around 25 MPG combined while maintaining strong towing capacity.

The drawback? Gas trucks lose more MPG when towing or hauling heavy loads compared to diesels. They also have shorter lifespans, and their resale value is often lower.

Head-to-Head: Diesel vs. Gas in 2025

Let’s compare two popular 2025 trucks: the Chevy Silverado 2500HD (gas vs. diesel) and a light-duty option, the GMC Sierra 1500 (gas vs. diesel).

• Chevy Silverado 2500HD:
  • Gas (6.6L V8): 16-17 MPG mixed, ideal for short trips or light towing. Offers a lower starting price ($51,600 base MSRP) and simpler maintenance.
  • Diesel (6.6L Duramax): ~18 MPG city, 21 MPG highway. Excels in heavy towing and long hauls but has a higher upfront cost and requires DEF. Real-world data from Fuelly shows 14.3 MPG average, with efficiency shining under load.
• GMC Sierra 1500:
  • Gas (2.7L TurboMax): ~19-22 MPG combined, great for daily driving or light tasks. More affordable and easier to maintain.
  • Diesel (3.0L Duramax): 23 MPG city, 29 MPG highway. Best for highway commuters or moderate towing, with Fuelly reporting 23.7 MPG real-world. Offers higher torque and longevity but comes with pricier fuel and maintenance.

Key Takeaway:

Diesel is the better choice for heavy towing, long-distance driving, or high annual mileage (over 30,000 miles), where fuel savings offset higher costs.

Gas trucks suit lighter duties, city driving, or budgets prioritizing lower upfront and maintenance expenses.

Real-World Factors That Affect Fuel Economy

Fuel economy isn’t just about the engine. Several factors influence your MPG:

• Driving Habits: Aggressive acceleration or idling burns more fuel. Diesels struggle with short trips due to warm-up needs.
• Load and Towing: Heavy loads hit gas trucks harder, significantly reducing MPG. Diesels handle weight better but still lose efficiency. Every 100 pounds reduces MPG by ~2%.
• Terrain and Weather: Highway driving favors diesels; city traffic suits gas or hybrids. Cold weather impacts diesel efficiency due to gelling risks.
• Vehicle Design: Aerodynamics, weight, and tire pressure matter. Modern trucks like the Silverado 2500 use lighter materials and 10-speed transmissions to improve MPG.

Cost Considerations: Beyond the Pump

Fuel economy is only part of the financial picture. Here’s how diesel and gas trucks compare:

• Upfront Cost: Diesel trucks cost $5,000-$10,000 more than gas models. For instance, the Silverado 2500HD diesel carries a premium over its gas counterpart.
• Fuel Costs: Diesel’s better MPG can save money over time, but only with high mileage. At 30,000 miles annually, diesel’s efficiency often offsets its higher fuel price.
• Maintenance: Gas trucks are cheaper to maintain due to simpler components and widespread mechanic expertise. Diesel maintenance, including DEF and particulate filters, is costlier but less frequent.
• Resale Value: Diesels hold value better due to durability and demand, though the initial premium may not fully recoup.
• Environmental Impact: Diesels emit less CO2 per mile but more nitrogen oxides and particulates. Gas trucks produce more CO2 but fewer pollutants. Both face strict 2025 emission standards.

Which Truck Is Right for You?

Your choice depends on your driving needs:

• Choose Diesel If: You tow heavy loads (10,000+ pounds), drive long distances, or plan to keep your truck for years. The 2025 Ram 2500 with a 6.7L Cummins (19 MPG city, 24 MPG highway) or the Ford F-250 Super Duty (up to 20 MPG highway) are top contenders.
• Choose Gas If: You drive in the city, haul light loads, or prioritize lower costs. The Ford Maverick Hybrid or Chevy Silverado 1500 with a 2.7L gas engine are excellent picks.
• Consider Hybrids: For a balance of efficiency and power, hybrids like the Ford F-150 EcoBoost offer gas-like affordability with diesel-like fuel savings for mixed driving.

The Bottom Line

In 2025, diesel trucks generally deliver 20-35% better fuel economy than gas trucks, especially for highway driving and heavy towing.

Standouts like the GMC Sierra 1500 Diesel or Chevy Silverado 1500 with the 3.0L Duramax achieve up to 33 MPG highway.

Gas trucks are closing the gap, with hybrids like the Ford Maverick hitting 42 MPG city and non-hybrids like the Ford Ranger offering solid efficiency for lighter tasks.

Your decision comes down to how you use your truck, your budget, and your workload.

Diesel shines for high-mileage drivers or those towing heavy loads, while gas or hybrid trucks are better for city commuters and casual haulers.

Calculate your annual mileage and towing needs, and test-drive both to feel the difference.

With 2025 trucks more efficient than ever, you can get the power you need without draining your wallet.