Shopping for a Ford F-250 diesel and wondering what kind of fuel economy you’ll really get? Here’s the truth: you won’t find official EPA ratings because the F-250 is exempt from those tests. But don’t worry—we’ve compiled professional reviews, real owner reports, and hard data to give you the numbers that actually matter for your wallet.
Why the F-250 Doesn’t Have Official MPG Ratings
The Ford F-250 Super Duty sits in a regulatory gray zone. Since it weighs over 8,500 pounds (its GVWR exceeds 9,000 pounds), it’s classified as a heavy-duty vehicle. This means it’s exempt from EPA fuel economy testing that applies to lighter trucks like the F-150.
This exemption dates back to the 1970s when vehicles this heavy were strictly commercial workhorses. Today, plenty of folks drive F-250s as daily vehicles, yet the regulatory framework hasn’t caught up. The F-250 falls under separate greenhouse gas standards measured in “grams per ton-mile” rather than simple miles per gallon.
What this means for you: all ford f250 diesel gas mileage data comes from third-party testers and real owners, not government labs.
What to Expect: Highway Driving Without a Load
Here’s where the 6.7L Power Stroke diesel shines. When you’re cruising empty on the highway, this truck delivers surprisingly strong numbers for its size.
Professional tests consistently show impressive results. Car and Driver achieved 20 MPG in their standardized 75-mph highway test with both 2023 and 2024 models. TFL Truck pushed that even higher, recording 21 MPG with a 2025 F-250 Regular Cab running the Standard Output diesel.
Real owners back this up. Forum posts and YouTube comments show F-250 diesel owners regularly hitting 19-23 MPG on highway trips. One High Output owner reported 22-24 MPG on interstate runs at 65-70 mph—but there’s a catch we’ll get to in a minute.
Your realistic highway target: 19-22 MPG for normal highway cruising. You’ll hit the higher end if you keep speeds at or below 70 mph and spec your truck smart (more on that later).
City and Mixed Driving: The Reality Check
Move into stop-and-go traffic, and the F-250’s 7,300+ pound curb weight becomes the dominant factor. Accelerating all that mass repeatedly takes fuel—lots of it.
Edmunds recorded 14.5 MPG in typical city driving with their 2024 test truck. Car and Driver’s “observed” fuel economy for mixed use came in at 15 MPG during their comprehensive evaluation.
Owner reports trend slightly higher at 17-19 MPG for mixed driving. This gap makes sense—professional testers often include performance runs and aggressive driving that pure city commuters don’t replicate. Your actual “city” number depends on whether you’re sitting in downtown gridlock or doing suburban errands.
Expect 14-15 MPG for pure urban stop-and-go driving. A typical suburban commute with some highway stretches will land you closer to 16-18 MPG.
Towing: Where the Numbers Get Complicated
Here’s where ford f250 diesel gas mileage becomes highly variable. The weight of your trailer matters, but aerodynamics matter more.
TFL Truck ran a revealing test that proves this point. They tested a 2025 F-250 diesel three ways: empty (21 MPG), towing an empty gooseneck trailer (12.1 MPG), and towing that same trailer with a 19,500-pound load (9 MPG).
Notice the pattern? Adding the trailer dropped efficiency by 8.9 MPG. Adding nearly 20,000 pounds to that trailer only caused another 3.1 MPG drop. The trailer’s profile creates massive aerodynamic drag—it’s basically a brick punching through the air. That’s why a tall, lightweight camper can get worse mileage than a heavy flatbed.
Light to Moderate Trailers (Under 12,000 lbs)
This covers most recreational use—campers, boats, and smaller RVs. The consensus from multiple owner reports shows you’ll get 10-14 MPG with typical trailers in this range.
One owner towing a 6,000-pound camper reported a steady 12 MPG. Another pulling a “large camper” (unspecified weight) saw 10-12 MPG. These numbers hold up across different truck configurations and driving conditions.
Heavy Towing (12,000-20,000+ lbs)
Now we’re talking serious fifth wheels and commercial gooseneck loads where the diesel engine earns its keep.
TFL Truck’s 19,500-pound road trip averaged 9 MPG over extended highway miles. Owner reports show similar numbers, with one hauling 17,000 pounds at 75 mph seeing 7-8 MPG.
Conditions matter enormously here. One owner towing a 12,000-pound fifth wheel into a 25-mph headwind watched fuel economy drop to 6.7 MPG. Another pulling 17,000-18,000 pounds through Vermont’s hills reported 4-6 MPG.
For heavy loads on mixed-grade highways, plan for 7-9 MPG. Add mountains or strong headwinds, and you’re looking at 4-7 MPG.
The Worst-Case Scenario: Ike Gauntlet
TFL Truck’s “Ike Gauntlet” test is the torture chamber for heavy-duty trucks—towing maximum weight up a 7% grade at high altitude. The 2025 F-250 Tremor with the High Output diesel managed 4.8 MPG during this climb, beating the Ram 2500 (4.9 MPG) and Chevy 2500 (4.6 MPG).
This isn’t your typical towing scenario, but it shows what happens in the absolute worst conditions.
How Your Truck’s Configuration Affects MPG
Not all F-250 diesels get the same fuel economy. Three key choices significantly impact your numbers.
Standard Output vs. High Output: Does It Matter?
Since 2023, Ford offers two versions of the 6.7L Power Stroke: Standard Output (475 hp / 1,050 lb-ft) and High Output (500 hp / 1,200 lb-ft).
Here’s the surprising truth: for most driving, there’s no meaningful MPG difference between them. The engines share identical boost, injection timing, and EGR settings up to the point where the Standard Output’s torque curve maxes out.
Owner reports confirm this. High Output owners report some of the highest unladen figures (22-24 MPG), matching or beating Standard Output trucks. You’ll only see a difference when towing so heavy that you’re exceeding what the Standard Output can comfortably handle.
Axle Ratio: The Choice That Really Matters
This is the configuration decision that dramatically affects ford f250 diesel gas mileage.
The rear axle ratio (3.31, 3.55, 3.73, etc.) acts as a torque multiplier. A lower numerical ratio (like 3.31) means the engine spins at lower RPMs for any given speed, improving fuel economy. Higher ratios (3.73, 4.10) provide more towing power but hurt efficiency.
The owner who reported the best unladen mileage (19-23 MPG) specifically ordered the 3.31 locker differential “to get the best mileage.” Meanwhile, trucks with 4.30 ratios consistently report worse numbers.
Here’s the trade-off: a 2024 F-250 4×4 diesel with a 3.31 axle can tow 15,800 pounds conventionally. That same truck with a 3.55 axle jumps to 22,000 pounds. You’re choosing between fuel efficiency and maximum capability, and this decision is permanent.
The Tremor Penalty
The Tremor off-road package adds a factory lift and aggressive 35-inch all-terrain tires. That hardware looks great and performs off-road, but it costs you at the pump.
TFL Truck’s test of a 2020 Tremor yielded 19.2 MPG on the highway, while their 2025 non-Tremor test hit 21 MPG. That’s a 1-2 MPG penalty for the off-road setup. Owners running even larger 37-inch tire packages report averages around 14.8 MPG.
The taller ride height increases aerodynamic drag, and those chunky tires add rolling resistance. It’s the price you pay for capability.
Diesel vs. Gas: The Real Cost Comparison
Many buyers struggle between the 6.7L Power Stroke diesel and Ford’s 7.3L “Godzilla” gas V8. The MPG difference tells only part of the story.
Head-to-Head Fuel Economy
Unladen, the gap has narrowed. Dealer estimates place the 7.3L gas at 15-18 MPG highway versus 18-20 for diesel. In mixed driving, the gas engine drops to 11-14 MPG while the diesel holds 15-18 MPG.
But towing? That’s where they diverge dramatically. Owner consensus shows the gas engine gets 6-9 MPG towing a camper, while the diesel delivers 10-13 MPG with the same load. That’s a 40-50% improvement when you’re actually working the truck hard.
| Driving Scenario | 6.7L Diesel | 7.3L Gas |
|---|---|---|
| Highway (Empty) | 19-22 MPG | 15-18 MPG |
| City/Mixed | 15-18 MPG | 11-14 MPG |
| Towing (Moderate) | 10-13 MPG | 6-9 MPG |
| Towing (Heavy) | 7-9 MPG | 4-6 MPG |
The Money Question
Fuel economy is only one piece of the financial puzzle. The High Output 6.7L diesel costs $12,495 more than the 7.3L gas engine. Diesel fuel often costs more per gallon than regular gas, and the diesel requires Diesel Exhaust Fluid (DEF), more expensive oil changes, and pricier fuel filter replacements.
TFL Truck noted their 2025 test truck “was using a lot of DEF” during extended testing. These costs add up.
The break-even point for the diesel option takes years to reach. You shouldn’t buy the diesel to save money—you buy it because you need its superior towing capability. If you tow occasionally or lightly, the 7.3L gas is almost certainly cheaper over the life of the truck.
How the Latest Models Compare to Older Generations
The F-250 got a significant redesign for 2023. Did it help fuel economy?
Yes, measurably. Pre-redesign models from 2020-2022 (which got the 10-speed transmission in 2020) showed strong highway efficiency of 18.9-19.2 MPG in testing. The 2020 model saw a 2-MPG bump from adding that 10-speed over the old 6-speed.
Current 2023-2025 models consistently top those numbers. Car and Driver hits 20 MPG, TFL Truck reaches 21 MPG, and owner reports push to 22-24 MPG. The redesign added roughly 1-2 MPG to highway efficiency through engine refinements and aerodynamic improvements.
If you’re cross-shopping model years, the newer trucks deliver real-world efficiency gains worth considering.
What Real Owners Actually See at the Pump
Let’s synthesize all this data into what you’ll actually experience.
For daily driving without towing:
- Pure city stop-and-go: 14-15 MPG
- Suburban mixed driving: 16-18 MPG
- Highway cruising: 20-22 MPG
- Best-case highway (3.31 axle, under 70 mph): 22-24 MPG
When towing:
- Light trailers (under 8,000 lbs): 12-14 MPG
- Moderate trailers (8,000-12,000 lbs): 10-12 MPG
- Heavy loads (12,000-20,000 lbs): 7-9 MPG
- Worst conditions (mountains, headwinds): 4-7 MPG
Configuration penalties:
- Tremor package: -1 to -2 MPG
- Higher axle ratios (3.73+): -2 to -3 MPG
- Larger aftermarket tires (37″+): -2 to -4 MPG
Which F-250 Diesel Configuration Is Right for You?
Your ideal setup depends entirely on how you’ll use the truck.
If you rarely tow (less than 15% of the time): Skip the diesel entirely. The 7.3L gas engine’s lower purchase price, cheaper maintenance, and close-enough unladen MPG make it the smarter financial choice. The $12,500 diesel premium will never pay for itself if the truck spends most of its life empty.
If you’re a weekend RVer (towing 40% of the time): This is the diesel’s sweet spot. Order the Standard Output engine with a 3.31 or 3.55 axle ratio. The 40-50% improvement in towing MPG (10-13 vs. 6-9 for gas) adds up quickly when you’re hauling regularly. The 3.31 axle maximizes your unladen efficiency for the other 60% of driving, while the 3.55 balances towing capability with decent economy.
If you’re towing heavy constantly (75%+ of the time): Go High Output with a 3.55 or 3.73 axle. You need the 1,200 lb-ft of torque and higher tow ratings. Fuel economy is secondary to capability here. The High Output won’t penalize your unladen MPG, and you’ll appreciate the extra power when pulling maximum loads.
If you want off-road capability: Accept the Tremor’s 1-2 MPG penalty as the cost of admission for factory lift and 35-inch tires. Then apply the diesel-vs-gas logic based on your towing frequency.
The Bottom Line on Ford F250 Diesel Gas Mileage
The modern 6.7L Power Stroke delivers impressive efficiency for a truck this size. You’ll realistically see 20-22 MPG on highway trips, 15-18 MPG in daily mixed driving, and 10-13 MPG towing moderate recreational trailers.
But here’s what matters more than raw MPG: configuration choices permanently define your truck’s efficiency. The axle ratio decision alone creates a bigger MPG swing than any driving habit you’ll adopt. A 3.31 rear end optimizes for fuel economy; a 3.73 optimizes for towing capacity. You can’t have both.
The absence of official EPA ratings isn’t a problem—it’s an opportunity to dig into real-world data that’s actually more useful than lab numbers. Professional testers and owner reports give you a clearer picture of what to expect in your specific use case than any government sticker ever could.
Choose your configuration based on how you’ll actually use the truck, not on hypothetical scenarios. If you’re honest about your needs, the ford f250 diesel gas mileage you achieve will match your expectations and justify the investment in this capable workhorse.
