Cars with the lowest journey cost

Some cars use more fuel than others, but since petrol, diesel and electricity have different costs, how can you compare them? Find out here

Sam Naylor
Dec 6, 2021

Keeping a close eye on your car's cost per mile figure is a helpful way of keeping on top of your motoring budget. This is especially the case during periods of very high petrol and diesel prices. So, what's the best way to do it, and which cars offer the cheapest journeys? Read on to find out.

First, let’s look at how to calculate how much a journey costs. The easiest way to do it is on a per-mile basis, so you can easily add up how much any given trip has cost you.

For this, you need your car’s miles per gallon, or mpg, figure (assuming it has a petrol or diesel engine). This can be taken from the official test (the current version is called 'WLTP' and is more realistic for real-world driving than the figures provided by the old 'NEDC' version), as we’ve done for the recommended cars below, but for a more accurate result, you can work out your car’s fuel economy from your own journeys.

Most modern cars give a readout of this on the dashboard, but for ultimate accuracy you'll want to follow this technique: fill the tank, drive normally for more than 100 miles and record the distance using the car's trip meter (reset this when you fill up), then refill to the brim again and log the trip meter reading.

Divide the number of miles driven by the amount of fuel used in litres, then multiply it by 4.544 (to convert litres to gallons) to get your mpg figure. It can be easier to leave it in miles per litre if you want to work out the journey cost.

Now you’ve got your fuel economy, it’s easy to work out the cost per mile - look at how much you paid per litre of petrol, multiply it by 4.544 and then divide by your fuel consumption (mpg).

Of course, this is only basing journey cost on fuel - there are other considerations such as VED (road tax), insurance and other costs such as breakdown cover that you can add in as well if you wish. Electric cars have a different formula based on per kWh home electricity cost rather than petrol or diesel prices, too.

The cars we’ve chosen below aren’t necessarily the absolute most economical cars you can buy, because listing them is an impossible task, given the complexities and differences in fuel economy testing formats over the years.

Instead, we’ve picked out two petrol, two diesel, two hybrid and two electric cars that are affordable to purchase and return excellent fuel economy both in the official tests and in our real-world experience, making these some of the most affordable cars with the lowest journey cost available now.

Cheap cars with great fuel economy

1. Skoda Citigo

Used deals from £5,245
Monthly finance from £0*

Our pick Skoda Citigo 1.0 MPIFuel economy 55.4mpg
Cost per mile 10pCost per 100 miles £10.84

 The Skoda Citigo is a small city car, and despite sharing the majority of its components with the Seat Mii and Volkswagen Up, it was cheaper to buy when new than either of those models - so it’s great value as a used car, too.

The small, low-powered 1.0-litre petrol engine in the Citigo (and the Up and Mii) means it isn’t fast by any stretch, yet it’s really economical no matter how you drive. Of course you can get better fuel economy by driving carefully but it’s good to know that this car will be cheap to run regardless of how carefully you drive it.

It has so many other good points that we just had to include it here. The Skoda is fun to drive, comfortable, relatively quiet even on the motorway, practical in five-door form and cheap to insure as well. It’s a superb first car but its appeal extends to just about any kind of driver on a budget.


2. Citroen C1

Used deals from £4,990
Monthly finance from £0*

Our pick Citroen C1 1.0 VTiFuel economy 58.9mpg
Cost per mile 10pCost per 100 miles £10.20

 The Citroen C1, Peugeot 108 and Toyota Aygo are all small city cars that share many mechanical parts, including a very efficient 1.0-litre petrol engine that should cut your costs per mile right down - and the low entry price only makes them even more attractive as a used buy.

We’ve picked the Citroen C1 here but all three are good cars and you should get the one you can find the best deal on. Their engines are the same so you won’t see much difference when it comes to journey costs. Low insurance and tax should keep all running costs low.

The C1 is fun to drive, although like the Skoda Citigo above its low-powered engine is much better at keeping running costs down than being fast in a straight line. It’s not too bad on the motorway but you do have to plan a long way ahead when overtaking or picking up speed.


3. Peugeot 208

Used deals Limited stock

Our pick Peugeot 208 1.5 BlueHDiFuel economy 71.4mpg
Cost per mile 8pCost per 100 miles £8.41

The current trend in the new car market is to move away from diesels, but the Peugeot 208 is one small car that bucks the trend. It’s available with an incredibly efficient 1.5-litre diesel engine, returning better fuel economy than our hybrid examples below.

The 208 isn’t quite at its best in diesel form, as we’d generally stick to a petrol model for short trips and around town. But, if you want rock-bottom running costs and spend lots of time on the motorway, then the 208 is a great way to achieve that.

The rest of the car impresses - the interior looks smart and there’s lots of modern technology inside as well. It’s relatively comfortable and quiet inside the cabin, too. It also serves up a blend of handling and comfort that makes it really enjoyable to drive.


4. Ford Focus

Used deals from £13,000
Monthly finance from £285*

Our pick Ford Focus 1.5 EcoBlueFuel economy 67.3mpg
Cost per mile 9pCost per 100 miles £8.93

If you need a larger family car than the city cars and superminis above, the Ford Focus is a good option. It’s great value for money and with the 1.5-litre diesel engine, it’s one of the most economical cars in its class, according to official tests.

It’ll certainly prove to be a cheap car to run in the real world, too. It excels on the motorway, where the diesel engine will be at its most efficient, and the Focus also has enough room inside for a family and a boot full of holiday gear.

The Focus also happens to be great to drive and very comfortable - in fact, it’s one of the best cars of its type in both respects. It has plenty of standard kit as well, so even low specification versions are worth a look.


5. Toyota Prius

Used deals from £12,495
Monthly finance from £0*

Our pick Toyota Prius HybridFuel economy 61.4mpg
Cost per mile 10pCost per 100 miles £9.80

Chances are, the Toyota Prius will be more than familiar to anyone living in a city, as it’s one of the most popular cars with taxi drivers. There’s a reason why; it's well-known for ultra-low running costs and impressive reliability. Those are great attributes in a car you're getting for yourself, too.

There’s an electric motor as well as a petrol engine, which means the Prius delivers strong fuel economy in town as well as on the motorway. It’s also incredibly consistent - it can match its official figures with ease, where other cars can struggle in normal driving.

Cost per mile won’t be an issue in the Prius and neither will comfort, as it’s incredibly smooth to drive. It’s not the most luxurious car to sit in but it’s so quiet, calm and comfy, so the Prius is a fantastic commuter car. It’s also a great family car as it’s roomy in the back.


6. Honda Jazz

Used deals from £18,500
Monthly finance from £0*

Our pick Honda Jazz 1.5 i-MMD HybridFuel economy 62.8mpg
Cost per mile 10pCost per 100 miles £9.57

The latest Honda Jazz is a hybrid, which means this small car is an interesting choice for those looking to keep their journey costs down. The petrol engine and electric motor can work independently, so all-electric running is even possible for short distances around town.

The Jazz is also hugely practical for a small car - it’s nearly as big inside as cars that are bigger on the outside and more expensive to buy. The Jazz is good value as a result, and the technology fitted inside is bang up-to-date as well.

It’s not very fun to drive for a small car, but if you prefer comfort and reliability then the Honda Jazz is well worth a look. It’s happy on the motorway, but makes the most sense as a car for short trips and city driving.


7. Seat Mii Electric

Used deals Limited stock

Our pick Seat Mii ElectricEfficiency 4.3 mi/kWh
Cost per 100 miles (standard/daytime tariff) £3.72Cost per 100 miles (cheap/overnight tariff) £1.16

One look at the cost per 100 miles figures of the electric cars on this list tells you all you need to know about life with an electric car. While the most economical petrol, diesel and hybrid cars cost somewhere around £8 per 100 miles, you’ll be paying less than half of this with electric cars.

The Mii Electric is very similar to a normal Mii, so it’s good to drive, comfortable and more practical than you might think. Its electric motor means it has some of the lowest running costs of any car.

However, with a range of fewer than 100 miles on a full charge, you’ll have to stop and charge up to actually travel 100 miles in one go. This means the Mii Electric only makes sense for those who drive short distances and can charge up at home or at work.


8. Hyundai Ioniq Electric

Hyundai Ioniq Electric front three quarters view

Used deals Limited stock

Our pick Hyundai Ioniq Premium SEEfficiency 4.5 mi/kWh
Cost per 100 miles (standard/daytime tariff) £3.56Cost per 100 miles (cheap/overnight tariff) £1.11

The Hyundai Ioniq Electric is a more rounded electric car than the VW e-Up (above) - it has enough room for a family and thanks to an official range of almost 200 miles, it’s possible to use it for all sorts of trips.

Yet it's more efficient than the Seat (according to manufacturer statistics, at least), and its cost per mile figure is similarly low. If you charge using Economy 7 pricing at night, you’ll pay well under £2 per 100 miles, which is just 2p per mile. You’ll need to live somewhere with access to a charger, but you’ll also never have to go to a petrol station again.

The Ioniq is also a really comfortable car that’s great for any kind of trip - it’s quiet and smooth, so whether you’re on a motorway or stuck in city traffic, it’s relaxing to spend time in. There’s also lots of high-tech kit included as standard.

The Ioniq is also available as a hybrid and a plug-in hybrid, so if you like the look of one but have different needs, there’s a good amount of choice in the range.


*Representative PCP finance - Ford Fiesta Titanium:

Monthly payments over 48 months: £192
Deposit: £0
Mileage allowance: 8,000 per year
Optional final payment to buy car: £2,923
Total amount payable to buy car: £11,926
Total cost of credit: £2,426
Amount borrowed: £9,500
APR: 9.9%

Buyacar is a credit broker, not a lender. Our rates start from 6.9% APR. The rate you are offered will depend on your individual circumstances.


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