Gas mileage – MPG calculator – how to save fuel easily

Gas mileage and efficiency of cars are becoming more and more important if it comes to buying a new car. On this site, you find calculators that will help you to find out if your car is fuel efficient. Furthermore, you will find valuable expert tips and important background information on how to save fuel.

Gas mileage calculator

The easiest way to calculate the gas mileage (MPG) of your car is to note down the following values when refueling your car:

  • odometer reading
  • the amount of fuel in liters or gallons
  • and the paid price for the fuel.

Then, once the gas is empty again, note down the final odometer reading and enter all these values into the calculator below. You will be surprised how easy it is.

Gas mileage comparison calculator

If you want to compare the MPG of two cars and how their respective fuel cost add up over time, please use the online comparison tool below.

Valuable expert tips to reduce gas mileage

  • Shift up quickly, if possible low-speed – not only while highway driving. After starting up, for example, you can immediately shift into 2nd gear.
  • Do not warm-up car before driving. Even for Diesel-powered vehicles, this is not needed anymore (in case they are not older than 10 years).
  • Drive with foresight. Every braking operation wastes energy as you have to accelerate again.
  • Avoid short distance drives whenever possible. The first few miles are particularly fuel-consuming in cold operation.
  • Remove unused items from the car. This applies not only to roof or bicycle racks installed on the car but also to everything superfluous in the trunk, such as beverage crates and cleaning utensils. More heavy cars always have a higher gas mileage than a lighter car.
  • Turn off any unused loads such as air conditioning or heating.
  • Too low tire pressure not only increases wear and tear but also increases rolling resistance. Therefore, follow the manufacturer’s recommendations and check the tires regularly for correct pressure to avoid underinflated tires.
  • Keep the engine and ignition in shape. Do regular car maintenance. Observe maintenance intervals when changing motor oil. Clean or replace the oil filter, plug connections of the ignition cables and spark plugs.
  • Decouple the clutch early enough and let the vehicle roll where appropriate. For example on the last mile before the traffic light or on longer stretches of motorway. Attention: Never disengage the motor from the vehicle when the slope is steep, as the motor has a braking effect.
  • Carpooling saves fuel and deepens friendships.
  • Finally, buy a more fuel-efficient vehicle.

How far can I get with my car?

How do tires impact the gas mileage?

A car with larger tires usually looks better proportioned and therefore chicer. There are, however, very good reasons to pick wheels with smaller diameters.

With the size of the wheels, fuel consumption and CO2 emissions increase and MPG decreases. The larger the wheel and tires, the greater the overall driving resistance of the car. This is because a larger contact area also means higher rolling resistance. Rolling resistance results from the deformation of the tire, which produces a sufficiently large contact area on the road. Every time the tire spins and springs, it absorbs energy. This energy absorption is called rolling resistance. The more energy absorbed by the tread compound, the greater the rolling resistance.

“After all, the tire contributes about one-fifth of the total consumption of the vehicle”

Holger Lange from the R&D department of Continental

Besides going for tires with lower diameters, there is also a very simple trick to avoid high gas mileage: having the right air pressure, respectively avoiding underinflated tires. 0.3 bar pressure lower than advised by the manufacturer generates a rolling resistance increase of six percent and an additional consumption of one to two percent. So checking the tire pressure every 2-3 weeks can save money.

In addition, there is a new trend coming up: tall-and-narrow tires. These are tires with a large diameter, which are narrow at the same time. This results in 20 to 30 percent less rolling resistance. However, one has to keep in mind that narrower tires produce less grip which means that you can drive through curves less quickly.

What is the better fuel? Diesel or Gasoline?

Since the Volkswagen Diesel scandal in 2017, Diesel-powered vehicles are all over the media. EPA investigated and Volkswagen had to buy back hundreds of thousands of cars. VW currently searches for ways to repair and fix them (from simple software updates to complete hardware retrofits). Once these cars would come as used cars back on the market, one could potentially make a very good deal.

Should you still consider buying a Diesel or not? Is the fuel efficiency of one of both better? The following pros and cons of the different fuels should be considered in your purchase decision.

Reasons for a Diesel-powered vehicle

  • Diesel engines provide more torque than gasoline engines. Even though the horsepower numbers are lower than for comparable gasoline engines, the 0 – 60 mph values are much faster. The acceleration feels stronger.
  • Diesel vehicles consume 25 to 30 percent less fuel than similarly performing gasoline vehicles. This means you have a lower gas mileage for the same driving distance (they have a higher mpg). Fuel efficiency is better.
  • Diesel is very efficient and dense in energy. It can be converted much better from heat into energy than gasoline. Hence it is also more environmentally friendly. But Nitric oxide (NO) and nitrogen dioxide (NO2) emissions need to be handled properly.
  • Diesel engines need less maintenance as they do not have spark plugs or distributors. Also, they last longer due to their construction because Diesel fuel has lower octane numbers and Diesel engines (also compression-ignition engines) do not compress the fuel. They only compress air and then inject Diesel heated by the Compressor into the air.
  • Current government pressure will likely result in better catalytic converters and filter systems. This will ensure that Diesel engines are eventually as low-emission as promised.

Reasons against a Diesel-powered vehicle

  • It is likely that the price for Diesel fuel is going to rise in the future.  Because it is also used by many alternative consumers (e.g. trucks, home and industrial generators, heating). This point is counter-effected by the lower gas mileage of Diesel engines.
  • Diesel fuel is rich in Carbon and has a composition close to heating oil. As a result, it burns more dirty and sooty. To prevent this cost-intensive filters and catalytic converters need to be installed. This can make a Diesel vehicle eventually more expensive than a Gasoline-powered car.
  • Finally, hybrids and battery-electric vehicles are on the rise. Maybe it would be worth waiting for 2 more years and rather invest in an electric car after 2018 with even lower emission and better fuel economy.

To sum it up: It is not an easy decision to go for a Diesel engine at the current moment. Lower gas mileage is certainly a positive argument. However, one should observe what happens in 2018. And then see whether the car industry has found reasonable solutions to the emission problems.  Or whether alternative engines such as hybrid (for example the Toyota Prius) or battery-electric (like a Tesla) will continue their success.

The newer the car, the less gas mileage it has. Newer engines are designed for efficiency and often come with turbos, significantly reducing the fuel consumption.

Should I buy a new car or a young used car?

Hardly any other question is asked more frequently when buying a car. Both variants offer advantages and disadvantages. Of course, you also need to define what kind of vehicle you are looking for: hatchback, sedan, SUV, convertible or station wagon?

When configuring a new car, you can be sure that you have all desired extras on board. Also, you can rely on the full manufacturer’s guarantee. While a new car provides these advantages, it is often quite expensive. In addition, the purchased vehicle quickly loses much of its value. As a young used car, the vehicle is often considerably cheaper. In the first year after first registration, a new car in average losses almost 25 percent of value. In the second year it is still around 15 percent, only then does it fall to five to nine percent a year. Used cars are therefore much more stable in value than new cars. But you are not the first owner. Sometimes you have shorter warranty periods. Also, you may have extras in the car that you don’t need – instead you may miss other equipment details.

And what about the gas mileage? Especially for young used cars being one to 4 years old, the slightly higher gas mileage in comparison to the newest model can be neglected. The higher fuel cost is easily compensated by the significantly lower cost of the car.