Buying, renting or leasing a car is only part of the cost of ownership. You’ve also got insurance, repairs and what we’re going to talk about today — fuel.

Or more specifically, fuel efficiency. Wait! Don't go! Fuel efficiency is genuinely more interesting than it seems and the difference between an efficient car and an inefficient car can be huge.

Let’s compare the least efficient car on LeaseFetcher — the Bentley Mulsanne — to something in the middle of the market — the Volvo XC90.

The Bentley manages an absolutely woeful 18.8 mpg compared to the Volvo’s slightly better 36 mpg.

If you drove 10,000 miles a year and paid £1.20 per litre of unleaded, here’s what each car would cost you to run each year.

  • Bentley Mulsanne: £2,901.76
  • Volvo XC90: £1,515.36

That’s a huge saving! (Although if you're driving a Bentley, you're probably not that concerned over £1,400!)

Also remember that I was comparing the Mulsanne to a middle-of-the-road car in terms of efficiency. When you compare it to a really fuel efficient car, the savings are even greater.

So, without further ado, let's dig into the 10 most fuel efficient cars I could find on LeaseFetcher!

The Fiat 500 doesn’t get by on its cute Italian looks alone. With a smart engine under the bonnet, this city car will have you smiling during every (infrequent) trip to the petrol pump.

The most fuel efficient option I could find was the 0.9-litre Twinair Turbo. While it’s small, Fiat’s two-cylinder unit packs a decent punch, managing 0-62 mph in just 11 seconds and a top speed of 107 mph! Toss in impressive emission performance — just 90 g/km of CO2 — and you’ve got a really impressive engine.

In terms of fuel efficiency, here’s what you’re looking at:

  • Urban: 61.4
  • Extra-urban: 83.1
  • Combined: 74.3
  • Average Real World Performance: 48.3

At the reported average real world MPG, you’re looking at a fuel bill of £1,129.46 across the same 10,000-mile test.

108 viewed this car 500 Hatchback View Gallery
6.9

Fiat 500 Hatchback

24 derivatives available

  • Doors: 3
  • Engine: 0.0 - 1.4
  • Fuel: D, P
  • Body: Hatchback
  • Drive: M, A
  • CO2: 88 - 140g/km

From £108.64 Per Month

Initial Rental: £977.76 inc VAT

Peugeot has a history of making outstanding small cars so it’s not overly surprising to see both the Peugeot 308 and 108 (featured later) on the list. (Quite where the 208 is, I’ll never know.)

Also, the five-door 308 is probably the largest car on my list, which makes its fuel performance all the more impressive.

The best unit I could find is the 1.2-litre PureTech start-stop engine, which — fun fact time! — has won the International Engine of the Year Award for 1.0-litre to 1.4-litre category for the past three years! (Okay, maybe fun fact was a push.)

The 110 bhp PureTech engine has all the uumph you could want, getting the 308 from 0-62 mph in a hair under 12 seconds. Emissions are very low too with just 95 g/km of CO2 emitted.

Here’s what you’re looking at for fuel efficiency.

  • Urban: 54.3
  • Extra Urban: 83.1
  • Combined: 70.6
  • Average Real World Performance: 50

With the 10,000-mile test, you’re looking at a fuel bill of £1,091.06.

77 viewed this car 308 Hatchback View Gallery
7.4

Peugeot 308 Hatchback

24 derivatives available

  • Doors: 3 - 5
  • Engine: 0.0 - 2.0
  • Fuel: D, P
  • Body: Hatchback
  • Drive: M, A
  • CO2: None

From £192.97 Per Month

Initial Rental: £1,157.82 inc VAT

As the only non-European manufacturer on the list, the Toyota Aygo is flying the flag for all the fuel efficient marquees based in far-flung countries.

Opting for a basic three-cylinder 1.0-litre engine with a five-speed gearbox, Toyota’s engineers manage to eek out every last drop of petrol. Its blistering light curb weight — just 890kg — probably helps too!

While emissions are good — just 97 g/km of CO2 emitted — performance is a bit lacklustre. A 0-62 mph time of 15.5 seconds means you’ll be mashing the accelerator a lot just to get up to speed.

Anyhow, here’s what your efficiency breakdown:

  • Urban: 56.5
  • Extra-urban: 78.5
  • Combined: 68.9
  • Average Real World Performance: 53.2

And for the 10,000-mile test, expect to pay around £1,025.43 for fuel.

21 viewed this car Aygo Hatchback (2014)

Toyota Aygo Hatchback (2014)

4 derivatives available

  • Doors: 3 - 5
  • Engine: 1.0
  • Fuel: P
  • Body: Hatchback
  • Drive: M, A
  • CO2: 95 - 97g/km

From £112.87 Per Month

Initial Rental: £677.22 inc VAT

Back we go to French marquee Peugeot to look at the 308’s younger brother — the Peugeot 108. Ignoring the diminutive all-electric iOn, the 108 is the smallest car in Peugeot’s lineup so you’d expect it do perform well at the pump.

The best engine I could fine is the 68 bhp 1.0-litre petrol fitted with a five-speed gearbox. While a 0-62 mph time of 13 seconds and a top speed of 99 mph won’t set your heart racing, Peugeot promises some jaw-dropping fuel efficiency numbers. Take a look:

  • Urban: 56.5
  • Extra-urban: 78.5
  • Combined: 68.9
  • Average Real World Performance: 50.7

You’re looking at around £1,076.00 for our 10,000-mile test.

46 viewed this car 108 Hatchback View Gallery
6.9

Peugeot 108 Hatchback

9 derivatives available

  • Doors: 3 - 5
  • Engine: 1.0 - 1.2
  • Fuel: P
  • Body: Hatchback
  • Drive: M, A
  • CO2: 88 - 99g/km

From £131.27 Per Month

Initial Rental: £787.62 inc VAT

Staying in France but moving marquees Citroen, it’s time to look at another diminutive French city car — the Citroen C1.

The best engine I could find was the VTi 68 with a manual five-speed gearbox. (Time for another fun fact! The VTi engines were actually developed in partnership with the BMW group from their Valvetronic concept.)

While the three-cylinder 1.0-litre VTi 68 engine is a little underpowered compared to its bigger brother — the PureTech 82 — it’s punchy enough for a small car. You’ll get from 0-62 mph in 13 seconds and will whir onto a top speed of 99 mph.

Here’s what you can expect at the pump:

  • Urban: 56.5
  • Extra Urban: 78.5
  • Combined: 68.9
  • Average Real World Performance: 49.8

On the 10,000-mile test, you should expect to pay around £1,095.44 for fuel.

85 viewed this car C1 Hatchback View Gallery
6.9

Citroen C1 Hatchback

9 derivatives available

  • Doors: 3 - 5
  • Engine: 1.0 - 1.4
  • Fuel: D, P
  • Body: Hatchback
  • Drive: M, A
  • CO2: 88 - 109g/km

From £114.07 Per Month

Initial Rental: £684.42 inc VAT

Yeah, I was surprised to see an Alfa on the list too. After all, you don't really associate Alfas with sensible and efficient performance. But when you check the spec, you see that the Alfa Romeo Mito actually uses Fiat’s fancy TwinAir engine so I guess that makes sense.

The engine — a two-cylinder 105 bhp 0.9-litre unit — is actually pretty exciting. It’ll get you from 0-62 mph in 11.4 seconds and onto a top speed of 114 mph, which isn’t bad for a fuel efficient hatch.

While its performance is a little worse than the Fiat 500, it’s still mighty impressive. Here’s what you can expect:

  • Urban: 56
  • Extra-urban: 74.3
  • Combined: 67.3
  • Average Real World Performance: 41.4

With one of the biggest disparities between official and real world fuel efficiency, the Mito is the poorest performance in out 10,000-mile test, costing around about £1,317.71.

31 viewed this car Mito Hatchback

Alfa Romeo Mito Hatchback

0 derivatives available

  • Doors: 3
  • Engine: 0.9 - 1.4
  • Fuel: P, D
  • Body: Hatchback
  • Drive: M, A
  • CO2: 89 - 130g/km

From £186.08 Per Month

Initial Rental: £1,116.48 inc VAT

As one of only two ‘luxury’ marquees on the list — the other is DS and is coming up later — you might expect the Audi A1 to perform a bit better than the rest.

Along with four different engines, they’ve also got four different wheel diameters and have tested the fuel efficiency with every combination.

The best combo I could find is the three-cylinder 1.0-litre turbocharged petrol with a manual gearbox and either 15 or 16 inch wheels.

Combined, you should manage 0-62 mph in a hair under 11 seconds and a top speed of 116 mph. Emissions are okay(ish) with 98g/km of CO2.

And your general fuel efficiency picture looks like this:

  • Urban: 56.5
  • Extra-urban: 76.3
  • Combined: 67.3
  • Average Real World performance: 45.7

On our 10,000-mile test, you’re looking at around £1,193.72.

87 viewed this car A1 Hatchback

Audi A1 Hatchback

0 derivatives available

  • Doors: 3
  • Engine: 1.0 - 2.0
  • Fuel: D, P
  • Body: Hatchback
  • Drive: M, A
  • CO2: 97 - 166g/km

From £185.66 Per Month

Initial Rental: £1,113.96 inc VAT

Like the Fiat 500 and the Alfa Romeo Mito, the Fiat Panda uses the wonderful 0.9-litre two-cylinder TwinAir engine. Even though the Panda is a little heavier and a little squarer than the 500, it hits some seriously lofty fuel efficiency numbers.

Here’s what you’re looking at.

  • Urban: 55.5
  • Extra-urban: 74.3
  • Combined: 67.3
  • Average Real World Performance: 49.8

With the 10,000-mile test, expect to pay around £1,095.44 for fuel.

65 viewed this car Panda Hatchback View Gallery
7.6

Fiat Panda Hatchback

16 derivatives available

  • Doors: 3 - 5
  • Engine: 0.0 - 1.2
  • Fuel: P, D
  • Body: Hatchback
  • Drive: M, A
  • CO2: None

From £124.09 Per Month

Initial Rental: £744.54 inc VAT

Guess what? We’ve got yet another small city car from a French marquee!

The Renault Twingo is actually the second smallest car in Renault’s lineup after the microscopic kart-esque Twizy. But the less said about the Twizy the better.

The Twingo is also one of the older cars on the list, first launched back in 1993 and most recently updated in 2014.

The most efficient engine is the 70 bhp SCe 70 engine which comes with stop-start as standard. It’s not the most powerful engine through and it takes 14.5 seconds to drag you from 0-60 mph.

  • Urban: 56.5
  • Extra-urban: 76.4
  • Combined: 67.3
  • Average Real World Performance: 46.6

And it’ll cost you £1,170.67 for the 10,000-mile test.

55 viewed this car Twingo Hatchback View Gallery
7.5

Renault Twingo Hatchback

4 derivatives available

  • Doors: 3 - 5
  • Engine: 0.9 - 1.6
  • Fuel: P
  • Body: Hatchback
  • Drive: M, A
  • CO2: 95 - 155g/km

From £147.90 Per Month

Initial Rental: £887.40 inc VAT

In case you missed it, DS is a new marquee spun out from Citroen in an attempt to market their cars to a more monied clientele. So that makes the DS3 the other luxury car on the list alongside the Audi.

Since DS is part of Groupe PSA (the group that includes Peugeot and Citroen), the DS3 shares the same engine as the Peugeot 308 — the 110 bhp 1.2-litre PureTech. And that’s a good thing considering it’s International Engine of the Year Award for three years running. (Fingers crossed for 2018!)

DS’s engineers have obviously geared the DS3 more for performance as, despite weighing a fair bit less than the Peugeot 308, it’s actually a touch less efficient. But it’s also a fair bit quicker, managing 0-62 mph in 9.6 seconds. That also makes it the quickest car on the list!

Anyhow, here’s what you’re looking at:

  • Urban: 53.3
  • Extra-urban: 74.3
  • Combined: 65.7
  • Average Real World Performance: 51.1

For our 10,000-mile test, you should expect to pay £1,067.58.

49 viewed this car DS 3 Hatchback View Gallery
7.2

Ds DS 3 Hatchback

7 derivatives available

  • Doors: 3
  • Engine: 1.2 - 1.6
  • Fuel: D, P
  • Body: Hatchback
  • Drive: M, A
  • CO2: 87 - 129g/km

From £155.80 Per Month

Initial Rental: £934.80 inc VAT