The number of miles that can be driven on a gallon of gas depends on several factors, including the vehicle’s fuel efficiency, type of fuel, driving conditions, and driving habits. With gas prices fluctuating frequently, getting the most mileage per gallon has become increasingly important for many car owners.
What impacts miles per gallon?
The most significant factor determining miles per gallon is the vehicle’s fuel efficiency rating. Plug-in hybrids and electric vehicles can achieve over 100 MPGe (miles per gallon equivalent), while large trucks and SUVs often get less than 20 mpg. The difference in MPG between vehicles can be drastic. Here are some key factors that affect fuel efficiency and MPG:
- Vehicle size and weight – Heavier vehicles require more energy to accelerate and move, lowering MPG.
- Engine size – Vehicles with larger, less efficient engines typically have worse fuel economy.
- Vehicle aerodynamics – The shape of a vehicle impacts wind resistance and drag. Less aerodynamic vehicles get fewer MPG.
- Fuel type – Standard gasoline has less energy than premium fuel, resulting in fewer MPG.
- Road conditions – MPG is better on smooth highways than congested city streets or off-road conditions.
- Tire inflation – Underinflated tires increase rolling resistance, reducing MPG.
- Driving habits – Aggressive acceleration and braking lowers MPG compared to smooth, defensive driving.
- Vehicle maintenance – Poor maintenance increases friction and lowers MPG over time.
- Vehicle load – Added cargo weight reduces MPG. Removing unneeded items can help.
Understanding these factors allows drivers to make changes that maximize their fuel efficiency and gas mileage. Properly maintaining a vehicle, avoiding excess weight, and driving conservatively provide the best mileage per gallon.
Average MPG by Vehicle Type
Fuel economy can vary drastically depending on vehicle type, size, and capabilities. Here are the average MPG ratings for common vehicle classes according to fueleconomy.gov:
| Vehicle Type | Average Combined MPG |
|---|---|
| Two-seater | 25-35 |
| Subcompact/compact | 28-40 |
| Midsize car | 25-35 |
| Full-size car | 20-28 |
| Sports car | 18-25 |
| Wagon/minivan | 22-30 |
| Small SUV | 22-32 |
| Midsize SUV | 18-26 |
| Full-size SUV | 14-22 |
| Pickup truck | 14-25 |
Drivers looking for maximum MPG will want to consider smaller, more efficient vehicle types. Family haulers and truck owners require more compromise between cargo capacity, passenger room, capabilities, and fuel efficiency.
MPG by Fuel Type
At a basic level, gasoline, diesel, and electric vehicles have innate differences in efficiency and miles per gallon. Here is how MPG compares by fuel type:
- Gasoline – Most standard consumer vehicles run on gasoline. Average MPG is 17-29 combined city/highway for non-hybrid gas vehicles.
- Diesel – Diesel engines provide more torque and often get 20-35% better MPG than gasoline counterparts.
- Electric – Pure electric vehicles use no gas and are rated in MPGe based on electric energy efficiency, typically 90-120 MPGe.
- Hybrid – Hybrids utilize gas and electric power and achieve excellent MPG around 40-55 combined.
- Plug-in Hybrid – Plug-in hybrids feature larger batteries and electric motors resulting in higher MPG over traditional hybrids.
Drivers that need to maximize MPG benefit from choosing diesel or electric vehicles. But gasoline power still dominates the market for repair costs, fuel availability, and affordability.
How to Improve Your Car’s MPG
While fuel efficiency ratings are inherent to each vehicle, there are ways drivers can optimize their MPG:
- Inflate tires to recommended PSI
- Use recommended motor oil
- Remove unnecessary cargo
- Avoid aggressive driving
- Plan routes to avoid congestion
- Don’t idle the engine
- Accelerate and brake gradually
- Limit air conditioning use
- Combine errands to reduce driving
- Get regular tune-ups and maintenance
Adopting fuel-efficient driving techniques is an easy way to start maximizing miles per gallon right away. Maintaining your vehicle properly over the long term also prevents decreases in MPG.
Driving Habits for Better MPG
How you drive makes a major impact on gas mileage. Aggressive driving like speeding, rapid acceleration and braking can lower MPG by up to 33% according to fueleconomy.gov. To maximize MPG, drivers should:
- Accelerate smoothly – accelerating gradually improves MPG significantly.
- Maintain steady speeds – varying speeds uses more fuel, so maintain a constant pace.
- Use cruise control – keeps a constant speed and saves fuel on highways.
- Coast to stop lights – avoids braking by letting off gas and coasting.
- Go easy on the brake – braking wastes energy, so brake gently.
- Avoid excess idling – idling gets 0 MPG, so only idle when necessary.
Following the speed limit, avoiding rush hour, combining trips, and planning routes also helps keep driving efficient and avoid congestion that lowers MPG.
How Maintenance Improves MPG
Good maintenance keeps a vehicle running at peak efficiency. Simple DIY tasks improve MPG including:
- Replacing air filters – prevents reduced airflow to engine.
- Checking oxygen sensors – ensures optimal air to fuel ratios.
- Changing spark plugs – prevents misfiring and improves combustion.
- Replacing fuel filter – allows optimum fuel pressure.
- Using recommended motor oil – reduces friction in the engine.
- Checking tire pressure – reduces rolling resistance.
- Performing alignments – corrects issues with tire angle.
Technicians can also spot bigger issues during oil changes and tune-ups before they decrease MPG. Addressing problems early maximizes gas mileage over the long run.
How Speed Impacts MPG
Driving speed has a measurable impact on MPG. Tests by fueleconomy.gov found:
- Most efficient MPG is achieved between 35-50 mph for gasoline vehicles.
- Driving above 50 mph rapidly decreases MPG due to wind resistance.
- Every 5 mph over 50 mph is like paying an extra $0.24 per gallon for gas.
- MPG was reduced by 15% when testing 75 mph vs 60 mph driving.
Highway cruising is most efficient near 45 mph. Slower city driving and congested stop-and-go conditions also consume more fuel making fewer highway miles ideal for better MPG.
City vs Highway MPG
MPG ratings account for a mix of city and highway driving. City MPG is often 20-30% lower than highway due to:
- More frequent acceleration and braking
- Lower speeds and engine RPMs
- More time idling at stoplights
Conversely, highway driving promotes better MPG with:
- More consistent smooth cruising
- Higher speed aerodynamics
- Less braking
So while each vehicle has a unique city and highway MPG profile, highway miles are universally more efficient and productive towards overall miles per gallon.
How terrain impacts MPG
The terrain you drive on effects MPG. Grades, curves, and elevation all contribute. In particular:
- Uphill driving reduces MPG – climbing steep grades requires more engine power and fuel.
- Downhill improves MPG – letting off gas and coasting downhill conserves momentum.
- Mountains decrease MPG – steep uphill and downhill segments consume fuel.
- Winding roads lower MPG – constant turning wastes kinetic energy.
- Flat straights maximize MPG – cruising without changing speed or direction.
While terrain can’t be changed, being aware of its effects helps drivers maximize MPG. Taking flatter routes when possible or using cruise control to maintain momentum through rolling hills can improve mileage.
MPG in Different Conditions
Beyond terrain and location, conditions like weather, seasons, and road quality impact MPG:
- Cold weather – reduces warm up time and lowers MPG up to 30%.
- Hot weather – causes A/C use which lowers MPG up to 25%.
- Rain – decreases MPG due to wet roads increasing tire resistance.
- Snow – significantly lowers MPG, especially with snow tires.
- Traffic – congestion and idling lowers MPG.
- Rural roads – gravel or dirt roads increase tire resistance.
- Tire pressure – just 1-2 PSI low hurts MPG by 0.2% per PSI.
Being aware of MPG loss from weather and road conditions helps drivers compensate through smart trip planning, vehicle preparation, and adjusting driving habits.
How to Calculate Your Car’s Real-World MPG
While EPA ratings provide a standardized MPG estimate, real-world results vary. To accurately calculate your car’s MPG:
- Fill up your gas tank and record the trip odometer.
- When refueling, note the amount of gas added in gallons.
- Subtract starting odometer reading from ending reading.
- Divide miles driven by gallons added.
For example:
- Trip start odometer: 34768
- Trip end odometer: 35126
- Miles driven: 35126 – 34768 = 358 miles
- Gallons added at fill up: 12.6
- MPG = Miles / Gallons = 358 / 12.6 = 28.4 MPG
Repeating this calculation over several tank fill ups provides an accurate real-world MPG average for your driving conditions and habits.
How to Maximize Miles per Tank
Since most vehicles only have a 12-20 gallon tank, maximizing miles per tank is important. Here are some tips:
- Use top tier gasoline to maximize energy density per gallon
- Keep tires inflated to recommended PSI
- Run errands together to avoid cold starts
- Remove excess cargo weight
- Drive at efficient speeds around 45-55 mph
- Use cruise control to maintain steady speeds
- Plan routes to avoid congestion
- Turn off the A/C if not needed
- Accelerate and brake gradually
- Avoid idling when possible
Getting every last mile out of a tank saves money and reduces fill ups. A few key adjustments to driving habits and vehicle condition can optimize mileage range.
How an EV or Hybrid Affects Miles per Gallon
Switching to a plug-in electric or hybrid vehicle is the most impactful way to boost MPG:
- Pure EVs use no gas and are rated in electric MPGe instead of MPG.
- Plug-in hybrids maximize electric miles before the engine turns on.
- Hybrids improve MPG using electric motors to supplement gas engines.
- EVs and hybrids recapture braking energy through regenerative braking.
- Electric motors provide instant torque for smooth acceleration.
Choosing an electric or hybrid vehicle is the best way to slash fuel costs, emissions, and trips to the pump. EV ranges now reach 300+ miles per charge, with hybrids achieving over 50 mpg.
How Much Could You Save by Improving MPG?
Better fuel efficiency directly translates to dollar savings over time. For example, improving from 20 to 30 MPG in a car driven 15,000 miles per year, with $4 per gallon gas, saves over $1000 annually:
- 20 MPG = 15,000 miles / 20 MPG = 750 gallons used
- 30 MPG = 15,000 miles / 30 MPG = 500 gallons used
- Gallons saved = 750 – 500 = 250 gallons
- 250 gallons x $4/gallon gas = $1000 saved
Maximizing MPG saves significant fuel costs over the years at today’s prices. And keeping MPG optimized prepares for future gas price increases.
Conclusion
Miles per gallon is greatly affected by your vehicle’s size, fuel type, terrain, conditions, and driving habits. Small efficient vehicles, steady highway speeds, and gradual acceleration maximize MPG. Maintenance and weight reduction also optimize it. Switching to a hybrid or EV provides the biggest MPG boost. Given high gas prices, monitoring and improving your MPG saves significant money over time.
