With the rising costs of gas, fuel efficiency has become an important consideration for car buyers. Good gas mileage allows drivers to spend less money filling up their gas tanks while reducing their environmental impact. But what constitutes good gas mileage? There are a few key factors to consider when evaluating the fuel efficiency of a vehicle.
How Gas Mileage is Measured
The most common way to measure a car’s fuel efficiency is through its miles per gallon (MPG) rating. This represents the number of miles a car can travel on one gallon of gasoline. MPG is calculated by dividing miles driven by gallons of fuel consumed.
For example, if a car is driven 340 miles before it needs to be refueled with 12 gallons of gas, its MPG would be 340/12 = 28 MPG.
In the United States, MPG ratings are provided by the Environmental Protection Agency (EPA) and appear on new vehicle window stickers. The EPA calculates these ratings through a combination of laboratory testing and real-world driving simulations.
City vs. Highway MPG
The EPA provides two MPG ratings for vehicles – city driving and highway driving. City MPG approximates a mix of stop-and-go driving and short trips, while highway MPG estimates a blend of rural and interstate driving in optimal conditions.
Highway MPG is typically 20-30% higher than city MPG because highways allow for more consistent optimal driving conditions. For example, a car might be rated at 22 MPG city and 30 MPG highway.
Combined Fuel Economy
Along with city and highway MPG, the EPA also provides a combined MPG figure that represents a weighted average of 55% city driving and 45% highway driving. This combined MPG gives a general sense of a vehicle’s overall real-world fuel efficiency across different types of driving.
What is Considered Good MPG?
So what constitutes good gas mileage? The answer can vary depending on vehicle type and personal needs.
Cars
For regular gasoline-powered cars, the average combined MPG is around 25-30 MPG. Compact and subcompact cars tend to have higher combined MPG in the 30-40 MPG range, while larger vehicles like SUVs often have lower combined MPG around 20-25 MPG.
Here are some general guidelines on good gas mileage for cars:
- Compact/midsize cars: 30+ MPG is good
- Full-size sedans: 25+ MPG is good
- SUVs: 22+ MPG is good
- Trucks: 18+ MPG is good
A combined MPG of 35 or higher is considered extremely fuel efficient for any regular gasoline-powered car.
Hybrid and Electric Vehicles
Hybrid cars that use both gas and battery power tend to achieve much higher fuel efficiency with combined MPG averaging 40-50 MPG. Good gas mileage for a hybrid starts at around 45 MPG.
Plug-in electric hybrids can offer combined MPG exceeding 60 or even 100 MPG equivalent (MPGe) when accounting for electricity usage. And battery-electric vehicles (BEVs) have no direct gas consumption, so they are rated in miles per kW-hour. Long-range BEVs typically achieve efficiency ratings of over 100 MPGe.
Trucks and SUVs
With trucks and SUVs, good gas mileage standards are a bit lower than for cars. Here are some guidelines:
- Small SUVs: 25+ MPG is good
- Midsize SUVs: 22+ MPG is good
- Large SUVs: 18+ MPG is good
- Pickup trucks: 18+ MPG is good
Any truck or SUV achieving a combined MPG over 30 is exceptionally fuel efficient.
Factors That Affect MPG
Why do some vehicles get better gas mileage than others? There are a number of factors that influence MPG performance:
Vehicle Size and Weight
Heavier vehicles require more energy output to accelerate and move, reducing MPG. Large trucks, SUVs and full-size sedans typically get worse fuel efficiency than smaller and lighter cars.
Engine Size
Vehicles with larger engines consume more fuel. Engine sizes are measured in liters (L) or cubic centimeters (cc). Smaller 4-cylinder engines offer the best MPG, while large 6- or 8-cylinder engines decrease efficiency.
Transmission Type
Automatic transmissions reduce MPG compared to manual transmissions. However, today’s automatics have closed the MPG gap through advanced technology like 8+ gear ratios.
Drive Type
Two-wheel drive options are more fuel efficient than four-wheel or all-wheel drive configurations which have additional drivetrain components.
Aerodynamics
Sleek and rounded vehicle designs that cut through the air encounter less wind resistance, improving MPG. Boxy shapes or features like roof racks worsen aerodynamics.
Performance
Vehicles made for speed and acceleration compromise efficiency for power. Sports cars and high-performance variants typically have lower MPG.
Fuel Type
Diesel engines offer about 15-20% better fuel economy than comparable gas engines. Hybrid powertrains also improve MPG through regenerative braking capturing energy.
Driving Habits
Aggressive acceleration, high speeds, frequent stopping, and heavy loads reduce real-world MPG. Following recommended driving techniques optimizes efficiency.
Best and Worst MPG Vehicles
To further illustrate the range of MPG across today’s vehicle market, here is a look at some of the vehicles with the best and worst fuel economy according to EPA ratings.
Best MPG Cars
| Make/Model | MPG City | MPG Highway | MPG Combined |
|---|---|---|---|
| Hyundai Ioniq BEV | N/A | N/A | 136 MPGe |
| Tesla Model 3 Rear-Wheel Drive | N/A | N/A | 133 MPGe |
| Toyota Prius Eco | 56 MPG | 53 MPG | 56 MPG |
| Hyundai Elantra Blue | 33 MPG | 43 MPG | 37 MPG |
Worst MPG Cars
| Make/Model | MPG City | MPG Highway | MPG Combined |
|---|---|---|---|
| Rolls-Royce Cullinan | 12 MPG | 20 MPG | 14 MPG |
| Lamborghini Aventador | 11 MPG | 18 MPG | 13 MPG |
| Bugatti Chiron | 8 MPG | 15 MPG | 10 MPG |
| Bentley Bentayga V8 | 12 MPG | 17 MPG | 14 MPG |
As shown, the most fuel efficient vehicles are electric or hybrid models, while supercars and ultra-luxury SUVs consume gas at high rates due to large powerful engines and heavy curb weights.
Improving Your Car’s MPG
While MPG is largely determined by the vehicle’s design, there are some steps drivers can take to maximize gas mileage:
- Accelerate and brake smoothly – aggressive driving wastes fuel
- Observe speed limits – wind resistance increases dramatically above 50 mph
- Avoid excessive idling to warm up the engine
- Reduce cargo weight and remove roof racks when not in use
- Check tire pressure monthly – underinflated tires increase drag
- Stay current on maintenance like air filters, spark plugs, engine oil
- Use the air conditioning sparingly
Adopting fuel-efficient driving techniques can improve a vehicle’s real-world MPG by 15-30%. However, choosing a more efficient vehicle based on EPA ratings makes the biggest impact on gas mileage.
Using MPG to Calculate Fuel Costs
One of the major benefits of good gas mileage is lower fuel expenditures. Drivers can use a car’s MPG rating to estimate annual fuel costs based on estimated mileage and gas prices with this formula:
Annual fuel cost = (Annual mileage / MPG) x Fuel price per gallon
For example, let’s assume:
- Annual estimated mileage: 15,000 miles
- MPG: 30 MPG combined
- Gas price: $3.50/gallon
Annual fuel cost = (15,000 miles / 30 MPG) x $3.50/gallon
= 500 gallons x $3.50/gallon
= $1,750/year
With the same mileage, a car getting 22 MPG combined would cost:
Annual fuel cost = (15,000 miles / 22 MPG) x $3.50/gallon
= 682 gallons x $3.50/gallon
= $2,387/year
The lower MPG car costs $637 more per year in fuel costs, demonstrating the significant monetary savings good gas mileage provides.
Cost Savings from Improved Fuel Economy
Trading in a low MPG vehicle for one with better fuel economy can yield major annual savings. For example, upgrading from an SUV getting 20 MPG combined to a sedan getting 35 MPG combined saves over $700 per year in fuel costs at 15,000 miles of annual driving with $4/gallon gas.
For those driving 20,000+ miles annually, the savings are even greater.
Choosing the Right MPG for Your Needs
When considering fuel efficiency for a new or used car purchase, it helps to assess your specific driving needs:
- Commuter vehicles – Prioritize high MPG since fuel costs make up a larger portion of operating expenses
- Family cars – Seek a balance of fuel efficiency with interior passenger and cargo room
- Performance cars – Focus less on MPG and more on acceleration, handling, horsepower
- Trucks and SUVs – Choose the most fuel-efficient model that still provides enough capability and utility
The goal is finding the “sweet spot” where the vehicle provides adequate power, functionality, and efficiency for your lifestyle at an acceptable fuel cost.
Conclusion
Good gas mileage is relative across vehicle types, but generally starts between 25-30 MPG combined for most cars and 18-22 MPG for SUVs and trucks. The most fuel-efficient vehicles achieve EPA ratings over 40 MPG combined or 100+ MPGe. MPG rankings allow consumers to evaluate annual fuel costs and savings from higher efficiency. While fuel economy largely depends on vehicle design, proper driving techniques can also optimize MPG. Choosing a car with excellent gas mileage based on your needs helps save money at the pump while reducing environmental impact.
