*The values used in this article are as of 2022-2023.
In this article, we’ll examine whether 18 MPG, or 13.07 L/100 km, is a reasonable fuel economy for a general automobile, and then we will discuss 18 MPG for specific vehicle types.
The focus will be on combined fuel economy. We will, however, briefly discuss city and highway fuel economy.
Is 18 MPG Good?
18 MPG is not a good fuel economy for a typical automobile. An 18 MPG car is 21.14% less fuel efficient than the 50th percentile vehicle, which gets 23 MPG. For specific vehicle classes, 18 MPG is the median gas mileage for pickup trucks, and 1 MPG better than full-size SUVs.
The table below shows how good 18 MPG is for several types of vehicles.
| Vehicle Type | Median Fuel Economy | 18 MPG is | 18 MPG/Median Difference |
|---|---|---|---|
| All Automobiles | 23 | Very Bad | – 21.73% |
| Sedan | 28 | Terrible | – 35.71% |
| Small SUV | 27 | Terrible | – 33.33% |
| Large SUV | 21 | Bad | – 14.29% |
| Sports Cars | 19 | Substandard | – 5.26% |
| Pickup Truck | 18 | Standard | + 0.00% |
As we can see in this chart, 18 MPG is within the 50th percentile for full-size pickup trucks and above the 50th percentile for full-size SUVs.
The median is a better measure of assessing whether or not 18 MPG is good. Electric vehicles and plug-in hybrids can significantly inflate average gas mileage values.
For example, we calculated that the average MPG for a pickup truck is 20.6 miles per gallon. However, 20.6 MPG is above the 70th percentile for all pickup trucks. That means for every 10 pickup trucks, 7 get lower gas mileage than the average of 20.6.
The median MPG, or 50th percentile, much better reconciles the large efficiency gap between electric and gas-powered vehicles.
18 MPG City
18 MPG in the city is not good. The median car (50th percentile) gets 20 MPG in the city.
18 MPG in the city is very bad for a vehicle with regenerative braking. The average hybrid (MHEV/HEV) vehicle gets 23 MPG in the city.
The fuel efficiency of a vehicle in the city is typically lower than its efficiency on the highway. Full-hybrid cars, on the other hand, are often more efficient in the city than on the highway because of regenerative braking systems.
18 MPG Highway
On the highway, 18 MPG is terrible fuel economy. It’s well below the median of 27 miles per gallon for highway driving. That’s an 8-miles per gallon difference. A typical 18 MPG highway rating translates to a combined (city/highway) gas mileage of 15 MPG for most vehicles.
The cost of 18 MPG
A car that gets only 18 MPG is going to cost you significantly more money to drive than the average vehicle.
At $5.00 per gallon, a vehicle that does 18 MPG will generally cost you $0.28 per mile. A 15-mile commute to work will cost you $4.17 in gas.
When driving 15,000 miles per year, the annual cost of fuel for a car that gets 18 MPG is $4167. At 18 MPG, you spend $905 more on gas than the median car.
How many miles is 18 MPG?
At 18 MPG, your car can cover a distance of 18 miles for every gallon of fuel. MPG (miles per gallon) is a measurement of how far your car can travel per gallon of gas. An 18 MPG car with a fuel capacity of 15 gallons can travel up to 270 miles before having to refuel.
18 MPG in L/100 km
18 MPG is 13.07 L/100 km. That means you will burn 13.07 liters of fuel for every 100 kilometers driven.
At 13.07 L/100 km, you can go 7.65 km with one liter of gas.
18 MPG on SUVs
For all SUVs, 18 MPG is regarded as poor fuel efficiency. However, there are a lot of factors to take into account before deciding whether or not 18 MPG is good fuel economy for a particular vehicle.
For example, 18 MPG might be decent gas mileage for a large SUV with a V8 engine but horrible for a small 4-cylinder SUV.
There are 2 main categories and 4 subcategories for SUVs: full-size and mid-size SUVs fall into the large SUV category, while compact and subcompact SUVs fall into the small SUV category.
To get a better idea of what you can consider good fuel economy for an SUV, please check out our articles covering the fuel economies of large SUVs and small SUVs.
We’ll take a look at each subcategory.
Full-size SUVs:
With respect to full-size SUVs, 18 mpg is slightly above average fuel economy. It is above the 70th percentile and 5.9% greater than the median fuel economy. The median full-size SUV gets average gas mileage of 17 miles per gallon.
18 MPG or above is usually seen in standard full-size SUV trims, typically fitted with 6-cylinder engines.
The 3.5 L, 6-cylinder gas engine Lincoln Navigator is a full-size SUV that achieves an average gas mileage of 18 MPG.
Mid-size SUVs:
For a mid-size SUV, 18 MPG is considered very low gas mileage. It is 3 miles less than the median MPG for the segment, which is 21 MPG. 18 MPG is the 25th percentile of the gas mileage for mid-size SUVs, which is bad.
18 MPG is generally seen in the least fuel-efficient 6-cylinder and most fuel-efficient 8-cylinder mid-size SUVs.
The 4.4 L, V8 2023 BMW X6 M50i is an example of a mid-size SUV that does 18 miles per gallon.
Compact SUVs:
For compact SUVs, 18 MPG is considered extremely poor fuel economy. It is 28% lower than the median and is well below the 20th percentile for all compact SUVs. The median fuel economy for this segment is 25 MPG.
There are no compact SUVs that have combined gas mileage ratings of 18 MPG. However, depending on the driving conditions, there are many compact SUVs that will get 18 MPG, such as the Porsche Macan GTS (19 MPG) and BMW X4M (17 MPG).
Subcompact SUVs:
18 MPG is the worst gas mileage you can get on a subcompact SUV. No subcompact SUV is meant to get an average fuel economy of 18 miles per gallon.
If you are getting 18 MPG or less on a subcompact SUV, it is likely due to poor driving habits or conditions. If not, then you should have the car inspected in a garage.
The subcompact SUV with the lowest gas mileage is the 2.0 L 4-cylinder Mercedes-Benz AMG GLA45 4matic, which gets 22 MPG.
18 MPG on Pick-up Trucks
Whether 18 MPG is good for a pickup truck mainly depends on what type of pickup truck you drive. The average mid-size gasoline pickup truck is 16% more fuel-efficient than its average full-size counterpart.
Pickup trucks that are fitted with bigger engines are typically expected to have a lower fuel economy than pickup trucks with smaller engines.
To get a better idea of what you can consider good fuel economy for pickup trucks, please check out our articles covering the fuel economies of mid-size and full-size pickup trucks.
Full-size trucks:
18 MPG is the 50th percentile of fuel economy for full-size pickup trucks. It’s not bad, but it’s not good either.
18 MPG is generally seen in full-size pickup trucks that have 8-cylinder engines. 8-cylinder pickup trucks get a gas mileage of 19-14 MPG. 18 MPG is an above 75th percentile fuel economy for a V8 truck.
An example of a full-size pickup truck that gets 18 MPG is the 2023 5.3 L V8 GMC Sierra 1500 SLT.
Mid-size trucks:
18 MPG is not good fuel economy for midsize pickup trucks. It falls well below the 25th percentile gas mileage for all midsize pickup trucks. The median MPG for this type of pickup is 21 miles per gallon.
The absence of V8 engines in mid-size pickup trucks is primarily responsible for the significant difference between full-size and mid-size. A large proportion (40-50%) of full-size pickup truck models are equipped with V8 engines, which have very low gas mileage, averaging 16 miles per gallon.
However, when fitted with the same engine, mid-size pickup trucks have very similar fuel economy as their full-size counterparts despite the weight difference.
18 MPG is at the lower end of gas mileage for 6-cylinder mid-size pickup trucks. It is most often seen in the most powerful mid-size pickup trims. An example of a mid-size pickup truck that gets a combined fuel economy of 18 MPG is the 3.5 L 6-cylinder Toyota Tacoma 4WD TRD PRO.
18 MPG on Sedans
As we can see in the above chart, which illustrates the different percentile ranges for sedans, 18 MPG is considered horrible gas mileage for a sedan in general.
Depending on the type of sedan you drive, the answer may vary. For instance, 18 MPG may be considered average for a V8 performance sedan, but awful for a mid-size family sedan.
To get a better idea of what you can consider good fuel economy for a sedan, please check out our articles covering the fuel economies of every type of sedan vehicle.
Full-size sedans:
18 MPG is a bad fuel economy for a full-size sedan. It falls below the 25th percentile and is 3 MPG lower than the segment’s median (50th percentile), which is 21 MPG.
You can generally expect 8-cylinder full-size performance sedans to get 18 MPG.
An example of a full-size sedan that does 18 miles per gallon is the 2022 6.4 L V8 Dodge Charger Scat Pack.
Mid-size sedans:
18 MPG is considered very bad for a mid-size sedan. It is 27% less fuel-efficient than the median mid-size sedan, which gets 26 MPG.
Most mid-size sedans that get 18 MPG are 6-cylinder performance cars. An example of an 18 MPG mid-size car would be the 2023 3.6 L 6-cylinder Cadillac CT4 V.
Small sedans (including hatchbacks):
You should not be getting 18 MPG on any compact sedan. These cars normally do between 28 and 35 miles per gallon, with the median being 31.5 miles per gallon. Getting 18 MPG with a small sedan is likely due to very poor driving habits or road conditions.
Similar to subcompact SUVs, small/compact cars with 4-5 doors should not achieve 18 MPG. The compact car with the lowest fuel economy is the 2.4 L 4-cylinder Subaru WRX, which has a 21 MPG EPA rating.
18 MPG on Sports Cars
18 miles per gallon is slightly below the median (50th percentile) for sports cars. It is within the normal range of what is expected for a sports car. It is good fuel economy for sports cars that have V8, V10, V12, and even W16 engines, but bad for ones with 4-cylinder and 6-cylinder engines.
A sports car that gets 18 MPG is the 2023 Jaguar F-Type R Coupe, which is fitted with a 5.0 L supercharged V8 engine.
Conclusion
Whether or not 18 MPG is a good fuel economy largely comes down to the type of vehicle you are driving. In a general sense, 18 MPG is a very poor fuel economy, as it is 5 miles per gallon lower than the median of 23 MPG for all automobiles. However, with respect to full-size pickup trucks and full-size SUVs, 18 MPG is considered to be a decent fuel economy.