Manual vs automatic cars: Which use more fuel?

Both automatic and manual cars have their supporters and detractors.

Some prefer automatics, as they’re safer, simpler – and easier to drive, particularly in urban traffic. What’s more, you can expect a well-maintained automatic to command a higher car valuation than an equivalent manual model.

Conversely, others swear by manual cars. After all, they cost less to buy and maintain – and are widely considered more fun to drive!

However, in 2023, with petrol and diesel prices remaining high, fuel consumption is now often a deciding factor when it comes to car purchases. So, how do manual and automatic cars stack up against each other in the fuel economy arena?

In this guide, we will clarify whether automatics consume more fuel - and how gearbox type can affect a car’s fuel consumption. We’ll also compare historic automatic and manual gearbox technology, before taking a look at the various types of modern automatic gearbox that are setting the standard today.

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Do automatic cars use more fuel?

In most cases, automatic cars actually use less fuel than their manual counterparts. Automatic cars are designed to use less fuel and save you money. In the long run, it can be much cheaper to drive an automatic car as opposed to a manual.

The main reason why automatic cars are generally better for your pocket is that they tend to have a better gear ratio, which means they use less fuel when driving at lower speeds. Some modern automatic cars also boast features such as improved engine efficiency and electronic transmission systems - both of which can help to reduce fuel consumption even further.

What is the relationship between fuel and gearboxes?

The relationship between fuel and gearboxes is complex, but understanding it can help drivers save money on fuel. Your car’s gearbox connects the engine to the wheels - and controls how much power is sent to them.

In vehicles with manual transmission, the choice of gear plays a major role in how efficiently the engine runs – and, as this is up to the driver, it can affect fuel economy. Conversely, automatic cars are designed to select the right gear for the vehicle without driver input.

In a manual vehicle, you will use less fuel by driving in a higher gear at a lower RPM (Revolutions per Minute) than if you drive in a lower gear at a higher RPM.

Driving in this manner has several benefits: it reduces emissions from exhaust gases (since less fuel is being burned), it allows for smoother acceleration whilst maintaining speed - and finally, it increases overall fuel efficiency by reducing consumption, therefore saving you money at the pump.

Why are older automatic gearboxes less fuel-efficient than manual systems?

In the past, automatic transmissions were almost always outperformed by their manual counterparts in the fuel efficiency stakes.

The reason for this is that the older-style automatic gearboxes usually comprise just 3 or 4 gears. As such, with these transmission systems, keeping the engine within an optimal RPM range is more difficult – particularly for cars with smaller engines.

Cars with older automatic gearboxes are often unable to adequately match the engine speed to the vehicle’s speed and have no way of taking advantage of certain 'sweet spots' in each gear.

This is not an issue with older manual transmission vehicles, which can shift into higher and lower gears according to the driver’s needs. In addition, old-style manual transmissions can reach optimal RPM ranges much faster than their automatic rivals, therefore making them more fuel efficient.

Are newer automatic gearboxes more fuel-efficient?

Modern automatic gearboxes with single automated clutches, dual-automated clutches and CVT (Continuously Variable Transmission) are becoming increasingly popular.

Compared with the older-style automatic gearboxes (which are now only found on large prestige cars with greater power and larger engine sizes), modern automatic gearboxes offer much better fuel economy.

Let’s take a more detailed look at the different styles of modern automatic transmission – and the benefits they each provide:

Single automated clutch

Single automated clutch transmissions use a small hydraulic system to manage the clutch when changing gears. This means that no manual input is required from the driver, resulting in more efficient gear changes and subsequently, better fuel economy.

Dual-automated clutch

Dual-automated clutch transmissions feature two separate clutches – one for odd gears and another for even gears. This helps to deliver a smoother driving experience.

CVT Transmission

Finally, CVT transmissions allow drivers to benefit from an extensive range of perfectly-spaced ratios, which help to maximise acceleration whilst optimising fuel consumption.

Which automatic cars have good fuel economy?

In the modern age, owning an automatic car can be the perfect solution for those who want to save time and money. With so many feature-packed models on the market in 2023, it can be difficult to know which ones are best for fuel economy.

Luckily, there are plenty of options available that offer excellent fuel efficiency without sacrificing power or performance.

When deciding which automatic car would best suit your specific needs, there are several factors to consider:

Lifestyle and design preferences

Personal preference is key; you should look for a car that suits your lifestyle (i.e. passenger space and storage requirements), whilst also matching your stylistic tastes. You should compare different models from various manufacturers to get an idea of what features they offer at each price point.
Vehicle type

A vehicle’s type can also influence its fuel consumption. For instance, smaller vehicles such as hatchbacks and superminis often have better fuel economy than SUVs.

Larger vehicles require more fuel (or power) to get from A to B. Despite offering many benefits over their compact counterparts (such as additional space, traction and towing capacity), larger vehicles often cost more to run.
Engine type

Smaller engines generally offer better fuel economy than their larger counterparts, but sometimes sacrifice power for efficiency.
Fuel or power type

Hybrid and electric cars tend to cost less to run than petrol or diesel vehicles. However, this is often reflected with a higher price tag. An electric car could be a savvy investment if you intend to sell your car in the next few years, as demand for EVs is expected to remain high for the foreseeable future.