MPG stands for 'miles per gallon' and refers to how many miles a car can travel using one gallon of fuel. It's a key measure of a car's fuel efficiency. A higher MPG means the car can travel further on less fuel, helping reduce costs and emissions.

Factors that impact MPG include your driving style, speed, tyre pressure, car weight, engine size, and car design. Hard acceleration, under-inflated tyres, and heavier vehicles can all reduce fuel efficiency.

How do I work out my car’s MPG?

To calculate MPG, fill your tank and note your mileage. Next time you refuel, record the litres used and miles driven. Use the formula: MPG = (miles driven ÷ litres used) × 4.546. This gives your car’s MPG based on real-world driving.

Is 45 MPG good in the UK?

Yes, 45 MPG is considered good fuel economy in the UK. It means the car can travel 45 miles using a single gallon of fuel. While hybrids can reach 60+ MPG, 45 is efficient for a typical petrol or diesel car.

No, 20 MPG is quite low by modern standards. It suggests your car uses a lot of fuel to cover a short distance, making it costly to run. If you want to save on fuel, consider switching to a more efficient car.

What is MPG? Car fuel efficiency explained

Q: Is higher MPG better?

Yes, higher MPG means better fuel efficiency. It allows your car to travel more miles using less fuel, which helps save money and reduces your environmental impact.

Q: How many MPG is good?

Generally, anything above 40 MPG is considered good. Over 60 MPG is very efficient, especially for hybrid or plug-in hybrid cars. Between 30–39 MPG is average, and under 30 MPG is considered poor for daily use.

Written by Joe Achillies Updated 17 Oct 2025

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Whether you’re looking for a new car or just trying to save money on petrol, it’s important to understand fuel efficiency. And when it comes to fuel efficiency, you’ll often hear the term miles per gallon or “MPG”. But what does MPG actually mean? And what is a good fuel efficiency for a car?

We’ve explained all, including what impacts MPG and what driving habits you can adopt to try and save on fuel.

What is MPG?

First, let’s start with what MPG stands for and what it actually means.

What does MPG mean?

MPG stands for ‘miles per gallon’. It tells you how many miles a car can travel on one gallon of fuel. In short, it’s a way of measuring car fuel efficiency.

For example, if a car has an MPG of 50, that means it can go 50 miles using just one gallon of petrol or diesel. The higher the MPG, the further you can drive without needing to fill up, which usually means spending less on fuel.

What impacts MPG?

Lots of things can affect your car’s MPG:

Driving style: If you brake a lot or accelerate hard it uses more fuel.
Speed: Driving faster than 60mph can reduce fuel efficiency.
Tyre pressure: Under-inflated tyres create more resistance and therefore use more fuel.
Car weight: The more weight your car carries, the harder it works! More weight can mean more fuel use.
Engine size and type: Larger or more powerful engines often use more fuel, while hybrids or smaller petrol engines tend to be more efficient.
Car make and model: Shape and aerodynamics can all affect MPG. Smaller, lighter cars usually use less fuel than big, heavy ones.

How car type affects fuel efficiency

If you’re trying to reduce your fuel spend, choosing the right type of car can make a big difference.

Smaller cars tend to be more fuel-efficient, simply because they’re lighter. They usually offer better miles per gallon, making them a great option for city driving or regular commutes. In contrast, larger vehicles like SUVs, vans, and performance models often have lower MPG figures due to their size, power, and weight.

Hybrid and electric vehicles are typically the most efficient overall, and many hybrids can achieve 60mpg or more! This is especially true in stop-start traffic where regenerative braking helps recharge the battery.

It’s also worth keeping in mind that even car body style can play a role. For example, saloons and hatchbacks are often more efficient than boxier shapes like 4x4s because they’re more aerodynamic.

What is a good fuel efficiency?

So, what counts as good MPG exactly? Let’s look at it in more detail.

Is higher MPG better?

Yes, higher MPG means better fuel efficiency. A higher number means you’ll go further on each gallon of fuel, which is better for your wallet and the environment.

If you do lots of long journeys, a car with good miles per gallon can help you spend less on fuel and reduce your carbon footprint.

How many MPG is good?

A good MPG for a car depends on the type of vehicle, fuel type, and how you use it. But generally, anything above 40mg is considered good. For most modern petrol or diesel cars, an MPG in the 40–50 range is typical. Hybrids and plug-in hybrids can sometimes go over 60 or even 70mpg in ideal conditions.

There’s no golden number when calculating fuel efficiency, but generally speaking:

Over 60mpg is considered very good
40–60mpg is good for modern cars
30–39mpg is average
Under 30mpg is usually seen as poor for everyday use

What is the average MPG for a car?

In the UK, the average MPG for cars is usually around 38mpg, with petrol cars slightly less efficient than diesel.

Average MPG on newer cars is often higher, thanks to better technology and stricter emissions standards. If you really want to save, considering a hybrid might be a good idea, as even 60mpg is much higher than average.

How to work out MPG

Wondering how to work out MPG yourself? It’s easier than you think.

Here’s a simple way to calculate MPG:

Fill your fuel tank to full and take a note of your current mileage.
Drive as normal until you next fill up.
Fill the tank to full again, noting how many litres you’ve added.
Record how many miles you’ve driven since the last fill-up.

Now use this formula:

MPG = (miles driven ÷ litres used) × 4.546 (There are 4.546 litres in a UK gallon).

The number you're left with is your MPG.

The takeaway

Whether you’re comparing cars, trying to reduce your fuel costs, or just want to understand MPG means, understanding average fuel consumption is important. It could help you save your hard earned money and make a big difference over time.

As well as choosing your car carefully, you can get the most out of your fuel tank by adjusting your speed and driving habits where possible.

Ready to start looking for your new car? Get a free quote today to see if you’re eligible for car finance.

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