Fuel economy is often the last thing on drivers’ minds but with fuel prices rising higher than ever this summer you may want to pay closer attention.

In this guide, Bumper breaks down what fuel economy is, how it’s calculated, which cars are the most fuel-efficient, and what habits may be costing you more on the road.

Fuel economy is how far your vehicle can travel in relation to the amount of fuel used. This is measured in miles per gallon (MPG).

If your car gets 40 MPG, that means you’ll be able to drive 40 miles on one gallon of fuel. The average for UK cars is 37.8 MPG.

Hybrids can usually achieve a longer range. For example, the 2016 Prius can achieve around 50 –55 MPG.

A metric used most frequently in the US is MPGe. This represents the number of miles an electric vehicle can travel using the equivalent energy produced by a gallon of petrol – 33.7 kilowatt-hours of battery power.

A study by What Car? which simulated motorway, rural and town driving, found the top 10 most fuel-efficient cars to be:

What could be causing my vehicle to use more fuel?

Changing your oil frequently can reduce fuel consumption.

For newer vehicles (registered after 2013), new technology and improved fuel consumption mean you should only have to change your oil every 7,000–10,000 miles.

For older cars, oil changes should be carried out around every 3,000 miles.

A study by Automotive Service Excellence revealed that worn spark plugs can reduce your fuel economy by up to 30%.

If your MPG begins to rapidly decrease, there’s a good chance your spark plugs are at fault.

Fuel injectors are responsible for delivering fuel to your engine. If a leak occurs and less fuel makes it to the engine your fuel economy will decrease.

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Oxygen sensors monitor the mixture of air and fuel. The incorrect mixture will decrease the efficiency of your engine.

Air conditioning is being used too frequently

 too frequently can harm your fuel efficiency, as unnecessary strain is placed on the engine.

Opening a window instead of using the air conditioning can help alleviate some of this stress, although it’s not advised to keep your windows down on the motorway as this causes additional resistance.

Turn off your engine where possible. Allowing your engine to idle in slow-moving traffic or outside school gates can be a big drain on fuel, so keep this to a minimum.

You can reduce your fuel consumption in a manual car by using the most appropriate gear. Both overworking and underworking the engine can have a negative effect on your fuel economy. When driving up a steep incline, use a low gear; when travelling fast on the motorway, use a high gear.

Common driving habits impacting fuel efficiency include driving too fast, accelerating too quickly and sudden braking.

Make sure to drive slowly with the flow of the traffic, and not just 

 Leave enough room between you and the vehicle in front, and allow the gears to naturally slow your vehicle.

Generally, keeping your car maintained with a regular service is a good way to reduce fuel consumption and improve fuel economy.

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 has been writing about cars for over seven years and writing for Bumper for over two, blending his passion for automobiles with a talent for storytelling.

Joseph has written about engineering and cars for Autozilla, Komaspec, and several engineering manufacturers. When he's not writing or tinkering with one of his five cars, Joseph dreams of owning an Alfa Romeo 33 Stradale.

Joseph Law

Bumper Content Writer

Reducing Fuel Consumption: A Complete Guide for Drivers