HonestJohn.co.uk launches Fuel Cost Calculator

Research by HonestJohn.co.uk reveals that diesel and ‘ultra-efficient’ cars are often a false economy, with motorists waiting the equivalent to 41 years to reap the financial benefits of some models.

Motorists have long been promised that spending more on diesel or ‘ultra-efficient’ cars will offer greater savings on fuel in the long run. But HonestJohn.co.uk’s Fuel Cost Calculator – a new feature to the site enabling motorists to easily compare two cars to find the lowest fuel cost – shows a different picture.

The research reveals that one of the worst offending diesel models is the Peugeot 208 Access+ 1.4 (Diesel) HDi 70 three-door. Purchasing a diesel model costs a buyer £3,050 more than the equivalent petrol model but offers the promise of a £75 annual saving on fuel. The bad news is that to break even on the initial extra cost would take approximately 41 years (14,898 days) or 408,165 miles of driving – the equivalent of driving around the earth 16 times.

When it comes to cars labelled ‘ultra-efficient’ by their manufacturers, it’s the Volkswagen Golf 1.6 TDI BlueMotion which is the worst value for money. To purchase the ultra-efficient model motorists pay £1,215 more than a standard Golf S 1.6 TDI on the basis of an annual saving of £132 on the cost of fuel. However for motorists to make that saving, the average driver would have to own the car for close to 10 years – that’s 92,281 miles.


The Volkswagen Golf S 1.6 TDI 105 three-door diesel model also overpromises. With an initial added purchase cost of £1,615, motorists would need to travel for 69,609 miles to break even with the petrol model. According to the official MPG figures for the Golf S 1.6 TDI 105, this would take the average motorist just under seven years (2,540 days).

Dan Powell, Managing Editor of HonestJohn.co.uk, said:“You may think you are going to make annual savings by paying the premium upfront but the average motorist is likely to change their car after 3-5 years so in many cases they never actually see a return on their money. Our Fuel Cost Calculator allows you to compare different cars and engines so that you can find the lowest fuel cost and make an informed decision about whether or not the car in question is suitable for your lifestyle and needs. The next time you’re thinking about buying a car, try out the Honest John Fuel Cost Calculator – we think you’ll be surprised at what you discover.”

The HonestJohn.co.uk Fuel Cost Calculator spans all makes and models in the UK, and encompasses petrol, diesel, hybrid and electric cars. It will also factor in electric charging point grants and battery hire, should these apply to the electric car in question, and it will work out London congestion charge savings if the car in question qualifies for an exemption.

Other cars that fail to live up to their promises when compared to similar petrol models, include: the ultra-efficient Ford Fiesta Zetec 1.0T EcoBoost 100 Start and the Skoda Octavia (2013) Greenline 1.6 TDI CR 110 5-door; both of which take around four years for motorists to make a return on their premiums. The Ford Fiesta Ecoboost is £1,000 extra and offers a £220 annual saving while the Skoda Octavia Greenline is £590 more and offers a £132 saving.

Many popular diesel models, including the Mitsubishi ASX (2010) 3 1.8 114 5 door and the Toyota Yaris (2011) Icon Plus 1.0 VVT-I 69 3-door, also appear to offer motorists less value for their money than the equivalent petrol models; both taking around 13-years for motorists to see a return on their purchase. The Mitsubishi ASX diesel costs £2,000 more with the promise of a £149 annual saving, while the Toyota Yaris costs £2,850 more and offers an annual saving of £218.

HonestJohn.co.uk’s research reveals that motorists get even less value for money when you consider that real world fuel consumption often differs to the figures released by car manufacturers. For example, it would take drivers of the Mazda 3 Skyactiv-D 2.2 SE 150 diesel model double the length of time to break even compared to the petrol model when using Real MPG figures. This is a hefty £2,250 premium for the promise of a £188 annual saving but this would take approximately 12 years (4,370 days) or 119,728 miles for the car owner to break even, according to official MPG figures. When compared with real world fuel consumption, it takes a shocking 24 years or 236,451 miles, before the driver would start making any savings.

To provide the most accurate readings, the calculator factors in some essential variables: car price, fuel type, average consumption, CO2 emissions and Vehicle Excise Duty (VED). By calculating all these variables, the calculator can work out a car’s fuel cost per 10,000 miles and compare it with any other model to reveal the lowest fuel cost.

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