/ Motoring

How many miles can your car really do on a full tank?

Car fuel dial

Like many motorists you probably have a good idea of how many miles your car can do on a full tank of petrol. But do you know if it is anywhere near what the manufacturer claims?

When I bought my car, I wanted a reasonably priced vehicle, that was small and easy to park, and not too expensive to run. I chose a Peugeot 107, with an advertised 508 miles on a full tank of petrol. But after a few months I noticed I never managed to get near that – the closest I ever got was 330 miles.

Obviously I didn’t drive until the tank was completely empty so it could have done a few more miles, but that’s still quite a difference between the real and claimed figures.

New Which? research put 200 cars through the same test and found that 98% couldn’t match or beat their miles per gallon (mpg) claim. The car that performed worst compared to its official mpg figure was the Mitsubishi Outlander PHEV (a plug-in hybrid), which overstated its mpg by 120%, costing £459 a year in unexpected fuel costs.

Other studies have shown that the gap between official test results and how we drive in the real world has increased over the past years, so the problem could be getting worse. But why is this happening?

Why fuel claims aren’t accurate

The problem lies with the Europe-wide test used to measure fuel use, the New European Driving Cycle (NEDC).

The test is called ‘new’ but it was introduced in 1970 and last updated in 2007. It’s outdated and doesn’t properly measure the kind of driving we do today, for example on motorways.

It also contains a number of loopholes. Manufacturers can, for example, opt to switch off air con and lights when testing, or increase tyre pressure above recommended levels. And as there is no standard way of testing, this means that you can’t make a proper comparison between different cars.

Many of you have already told us you knew the claims were misleading. Malcom R told us in 2013: ‘EU fuel consumption figures do not represent real-life, and are not intended to.’ Vynor Hill said: ‘Manufacturers’ claims are of no use to anyone.’

It seems unfair that a product that isn’t meeting its claimed performance doesn’t suffer any consequences and consumers just have to bear the brunt of it, or do their own research.

Steering in the right direction

A new and improved fuel efficiency test that would address many of the current one’s weaknesses is due to be introduced in 2017 by the European Commission (EC). This actually closely mirrors our own test and more accurately estimates fuel use.

But some factions are trying to stall the introduction of the new test to delay it to 2020. That would be another five years of useless fuel claims.

We don’t think this is right, and are urging the EC to stick to the planned timing, so that you won’t be taken for a ride any longer.

Do you think official miles per gallon figures reflect reality? Do you agree the EC should bring in the new test by 2017?

Simon says:
24 July 2015

Three months ago I took delivery of a Volvo XC60 D4 R-Design. This car offered the best mpg in it’s class of almost 63mpg. Whilst I expected not to quite get this, I have never been anywhere near this figure. My average after 6000 miles is 43mpg, 30% less. The best achieved has been 46mpg on a long motorway run and normal speeds. Volvo dealerships have repeatedly fobbed me off saying the car needs to “loosen” up and would get better after 3000 miles, then they claimed 5000 miles. So at 6000 miles I feel as though Volvo are completely misrepresenting , if not blatant lying, the true economy figures for the supposed new D4 engine. This will cost an additional £650 a year in fuel costs. So I do not recommend to anyone to buy an XC60 based upon fuel economy. This has soured the enjoyment of a new car as the car itself is good to drive.

Adrian du Plessis says:
25 July 2015

I bought an automatic petrol BMW 1 series, two years ago. The manufacturers claim an average of 49mpg. I regard myself as a conservative and light-footed driver (being of a certain age, heavy acceleration etc are not my style). I get 39mpg – this includes very little in town driving – most of the miles are done out of town.

This is very disappointing – apart from this I like the car very much. But the claim made by BMW is outrageous, so misleading as to be useless as a guide when buying.. I expect better from this brand.

Honest John gives readers submitted “real life” mpgs. For the Volvo it is 39.8 mpg, for the BMW 116i 41 mpg (118i 31.3.). So it seems like you are both getting typical real life mpg.
Blame the discrepancy on the EU test that manufacturers have to use, and the mpg that gives is the only figure they can publish – it is not a “manufacturer’s claim” (unless the salesman told you that the EU figures would be achieved).

The short term fix to this silly state of affairs is for everyone involved – manufacturers, Which?, dealers – to make it quite clear that the test results are largely useless and to point motorists to sites where “real life” figures are published. Then at least we won’t be “misled”. Don’t hold your breath for the new improved test though – it is still unlikely to give “real life” figures although it may be closer, so real life sites (and Which? test results) will still be needed.

Jon Harris says:
25 July 2015

This ‘campaign’ is starting to border on the laughable I’m sorry to say. Rather than blaming an ‘out of date’ test you’d be doing your readers/subscribers some service by explaining some very basic principles impacting fuel consumption rather than just pandering to them.

The whole point of the test, indeed any test, is to offer a guide that’s repeatable rather than advise of an absolute level of economy that every individual will achieve no matter how they drive.

Curiously i had a Citroen C1 as well and, in mixed driving, regularly got over 450 miles to the tank and over the 26k miles i owned the car i averaged 64.2mpg fractionally above the official combined figure of 62mpg.

The difference of course is not only the roads driven, but HOW a car is driven and that makes a HUGE difference to the economy achieved. An example of this is an experiment i did with a Panda multijet. One week i drove economically and achieved 74mpg, the next week on the same journeys but driving much more ‘enthusiastically’ the same car achieved 58mpg. If you can explain how any standardised test, including your proposal, can take that into account and give everyone a good, accurate, indication of the economy they will achieve, I’m all ears.

In the meantime, rather than adopt a frankly rather ludicrous stance how about actually helping those who are getting poor economy to understand how they might change their driving style and save hundreds a year? Just a thought.

Jon, the NEDC test does give results that are poor and, because of changes in car technology since it was introduced, I’m not even sure the results are consistent to make real comparisons. A more up-to-date test with a stricter procedure will help achieve the prime objective – to make emission comparisons between cars better and nearer reality so that compliance with EU emissions limits can be checked.

As you say, driving style, the topography where a car is generally driven, length of normal journey, how loaded the car is, tyre pressures etc will all affect mpg, and quite significantly. “Real life” figures supplied by enough real motorists will give the best indication of what you might achieve and we should point people at the sources for these.. The problem here is that emissions are required before a car is launched so real life figures will not be available for a while, and emissions cannot be measured reliably, I understand, “on the road” (but I might be misinformed here).

Both emissions and mpg matter – the former for VED and benefit in kind tax, the latter directly affects your wallet.

Steve Lambe says:
26 July 2015

I have a 2013 Mercedes SL350 (3500cc petrol) I have had it from new the fuel consumtion is what Mercedes said & sometimes better, the car averages 35mpg motorways 37 to 41mpg the best I have got is 43mpg averaging 50mph over 90 miles, I get better mpg than people I know with smaller engines, allots of this is down to driving styles and looking after your car, simple things like tyres pressures, regular servicing, driving sensibility if you drive like your racing you will get fuel consumtion to match

When I bought my Nissan quashquai 1.6 petrol cvc(auto) in November 2013 I understood the fuel consumption was in excess of 56 mpg. In reality I struggled to get 25 around town and 29-30 mpg on a run,and that was being a good boy sticking to the limits. The only way I could get 56 plus would have been travelling everywhere downhill. I appreciate autos do less to the gallon but half as much ??.needless to say couldn’t get rid of quick enough,my bit and last bit for British Engineering cost me too much money.

For a 2007 model 1.6 CVT Honest John gives an overall “official” mpg of 44.1 mpg, and a “real life” achieved of 35.1.

eric wolstenholme says:
28 July 2015

I bought a Toyota Prius in 2010. The claim was that it would achieve 73 mpg ON A REGULAR BASIS.This was plastered all over the dealer’s premises. The salesman had told me that short journeys, like going to the local shops would be fuel free – totally electric.

The car was a demonstrator and had been driven by the group managing director. When I collected the car the display showed 44 mpg! I queried this and was told he was a ‘heavy driver’! Now I could get 70 mpg from the car if I discounted the first few miles on choke and started the measurement on a downhill start to a long journey. However, normal all round driving was never more than 45mpg and far worse than this for the first few miles. So much for free trips to the shops!

I told the dealership that they were contravening the trade descriptions act but they insisted their claims were correct in the face of my experience.

I don’t know what Toyota had to say in 2010, but their website now states: “All mpg and CO2 figures quoted are sourced from official EU-regulated test results. These are provided for comparability purposes and may not reflect your actual driving experience.”

‘May not reflect your actual driving experience’ is a bit of an understatement. 🙁

Andy Holding says:
29 July 2015

Figures shown are brim to brim calculations, as onboard computers tend to be 10% optimistic.

A 2005 VW Golf TDI averaged 58.07mpg Official combined = 48.7mpg

My 2013 Audi A3 1.6TDi averages 60.32mpg Official combined = 74.3mpg

My Jaguar F-Type3.0 S averages 28.28mpg Official combined – 31.0mpg

Firstly the Golf exceeded the Official Combined figures, so has the test changed since 2005.
Secondly, I drive the Audi for economy but it’s 23% short of official figs, Whereas I don’t drive the F-Type for economy and it’s only 10% short of official figs.

Others have told me that their computers are optimistic about fuel consumption. On two occasions I have checked the accuracy of the fuel consumption meter on my Golf 6, it has been remarkably close to what I have measured by filling to the brim. I wish the same could be said for the fuel gauge which does not move off the full mark for at least 100 miles. 🙁

I looked at the Honest John website a few months ago and there was no useful advice to help make the information useful. For example, it would have been useful to suggest ignoring what the computer says and basing measurements on brim to brim calculations.

I record the mileage at each fill up and the quantity of fuel purchased – a habit from company car days. On the assumption the miles are fairly accurately recorded (presumably includes keeping your tyres at the correct pressure unless your car uses it’s Satnav) this should give a pretty accurate consumption. Mine is close to the computed figure.

Beryl, in another conversation, provided a link to John Cadogan – AutoExpert.com.au – who discussed measuring fuel consumption and flawa in the brim to brim method. Worth a look – an entertaining analysis.

Nigel Hughes says:
30 July 2015

I disposed of a 7-year old Toyota Corolla 1.4 diesel in January 2015. It had given an average of about 58 mpg in mixed running, not far from the claimed figure. I bought a Yaris hybrid. On its first mixed motorway and country road trip it recorded a mere 52 mpg. Mpg improved over the next 3000 miles or so. I recently did a trip from Alton to Northampton, recording 69 mpg each way. This was boosted by 20 miles of 50 mph cruising through the M3 roadworks and traffic on the M25 and M1 keeping cruising speed to between 60 and 70 mph. I am now averaging about 65 mpg. That is roughly what I had hoped for, given the mpg of the Corolla diesel.

Diddled says:
3 August 2015

I bought a Kia Picanto 6 years ago and I was impressed by the 64mpg claim in the brochure.
I have never got close to it though possibly for several reasons. Stop/start trips, cold weather and the quality of the unleaded petrol. I sometimes drive 40 to 100 miles although average is 10.
The average consumption is 48 mpg with a very few trips at 50 mpg. I record all miles and petrol purchases. Hope this helps you.

SuezY says:
6 August 2015

I purchased a Ford Focus 1.6tdci 2 1/2 yrs ago expecting to get around 67.3 mpg. I do around 17000 miles per year, if not more and the mileage is now at 56000+.
The average mpg I receive is now a consistent 55 to 57mpg… At least 10 mpg less than the official figure quoted.
The only way…. & I have done this, to get anywhere near or substantially beat 67.3mpg is if I drive at 50-60mph, then the figures have ranged from mid 60s mpg to the early 80mpg.
This may be a speed used by some, but I drive a lot on A roads & motorways, so it is not realistic for me to do.
Car manufacturers need to be honest, as a lot of people… including myself, used their figures as a guide & sometimes the main reason in deciding which car they would purchase.

SuezY, Honest John quotes “real life” (i.e. drivers reported) mpg of 51 to 54 mpg so you are doing pretty well. The fallacy here is suggesting that the figures advertised represent what will be achieved and are therefore dishonest. It is the outdated EU test that gives false figures, and these are the only figures that manufacturers can declare.

We need to stop publicising this disparity as down to dishonest manufacturers and simply publish the facts. Pointing buyers towards “real life mpg” websites would be a more useful and positive approach, but criticising manufacturers attracts much more publicity.

My 2014 Skoda Yeti 1.2 is a lovely car, but its fuel consumption is horrendous, nowhere near the official figures claimed on the website. The latter are 42.2 mpg (6.7L/100km) urban; 58.9 (4.8 L/100km) extra-urban; 51.4 (5.5) combined. Even driving it like a childrens’ pony I’m more likely to get 9L/100km urban; 7.5 extra-urban; anything from 6 to 12 L/100km in mixed conditions. When my wife drives it like a normal car it’s even worse. I reckon going up hill with a full load you could actually see the fuel gauge going down (I’ve never tried it).The dealer claimed it would it get 40 mpg (so less than the manufacturer), but only in the gentlest conditions will it do that. One reason of course is that this is a very heavy car, especially by today’s standards. Another is that this petrol engine is turbo-charged. I cannot for the life of me understand why this is the only petrol engine available on this model. The diesels cost over £1000 more. It should be said that none of the car reviews I read mentioned this reality. All of them talk of 43-44 mpg mixed. So they’re no more reliable than the manufacturer, a major disappointment.

I find that driving in hilly areas markedly decreases the fuel economy in my car and others I have driven, judging from the indicated mpg. Using little fuel going down the hills certainly does not compensate for the amount used when climbing them.

Michael says:
13 August 2015

My experience seems typical, although I have always been cynical about claimed fuel consumption so I am not genuinely disappointed. I drive a Skoda Octavia 1.4 TSI petrol-engined (DSG) automatic model bought in December 2013 which is an excellent trouble-free car and despite driving it very gently in Economy mode in a very flat part of the country and rarely exceeding the legal speed limit, even on motorways, it never reaches the fuel consumption performance that was claimed.

46.3 is the advertised “urban” and typically I get 37 or 38.
64.2 is “extra-urban” and 55 is probably the realistic figure.

Judging by the speed of those who might be regarded as more typical (and surely the more cautious driver is not typical) I cannot imagine that in the Normal/Drive mode, without the benefit of coasting when you take your foot off the gas, anyone would be able to achieve figures as good as mine.

Late to this thread. Ditto I have always been cynical about the published claims. I got a new car earlier this year and, to their credit, most sales people I dealt with were hesitant on the official MPG figures. But none were able or willing to give me an idea of what I could expect.

I do have a bone to pick with Which on their car report. Have a look at the BMW X3 and X4 in this report. 3 and 1 stars respectively on fuel economy. These cars are basically the same car – same engines, same published weight, but different body shapes- with the X4 arguably being slightly more aerodynamic. Did the which testers here do a like-for-like comparison here? Or test the 2.0 diesel on X3 and 3.5 on X4? I struggle to believe the ratings here, and as such this makes me wonder what other car ratings are questionable.

Additionally, I think any fuel rating is only valid when specified with a specific model, to enable us the reader to do like-for-like comparisons. Trying to apply one rating to cover engines from say 2.0 to 3.5 diesel, or worse 1.8 front wheel drive petrol to 4.0 diesel AWD is pushing it (IMHO 🙂 )

This debate has now been going on for some months. So what are you going to do about it, Which ?

VW are in trouble in USA. It is alleged they installed software in their 4 cylinder diesels that can disable pollution control (which then enhances performance) but enables it during pollution testing. The result is much higher nitrous oxide emissions in normal use. so potentially 500 000 cars (VW and Audi) being recalled, huge penalties, and possible criminal indictment in prospect.

The thought crosses my mind that if they do this in the States, might they not do it in Europe to enhance their pollution figures? Doing so would lead to interesting consequences.
1.The EU penalises manufacturers heavily if their “fleet” (total annual production) produces average emissions above the EU target.
2. European states derive VED (or equivalent) based on emissions, so could well be short changed.
3. Many countries tax employees with company cars based on emissions – again possibly short changed.
4. Published mpg may well be even better than it should be, so motorists could be losing out further on fuel consumption. (I know EU NEDC figures are not realistic anyway but they are the official data that must be published).
All could add up to huge penalties here as well, including compensation for individual motorists.
That is, if it is all true.
It will be interesting to see how the USA case develops, and whether the EU has any similar information that it will follow up.
I wonder if this has any connection to the disparity in mpg that BEUC are pursuing in Italy against Fiat and…….VW?

European states derive VED (or equivalent) based on emissions, so could well be short changed.

But not the UK any more, sadly…

The UK has 13 tax bands based on CO2 emissions ranging from annual VED of £0 up to 100 g/km, £30 up to 110 and rising to £505 at 255 and over (and a first year VED of £1100).
In Europe “The 20 EU countries that levy passenger car taxes partially or totally based on the cars’ CO2 emissions and/or fuel consumption are: Austria, Belgium, Croatia, Cyprus, Denmark, Finland, France, Germany, Greece, Ireland, Latvia, Luxembourg, Malta, the Netherlands, Portugal, Romania, Slovenia, Spain, Sweden and the United Kingdom.”
It seems to me these could all lose heavily if emissions are falsified by manufacturers.
As the alleged fiddle has been going on for the last 6 years there is considerable retrospective loss of tax revenue and fuel refund.
Unless I have misunderstood something?

Sorry, Malcolm; my rejoinder was because of the new policy from the Tories:

From the VED site:

“From April 2016 there will be a flat standard rate of £140 for all cars except those emitting 0 grams CO2/km for which the standard rate will be £0. ”

So the UK has abandoned any pretence of encouraging low emission vehicles.

Ian, thanks for that – I wasn’t aware of the change. I see it applies to all new cars registered after 1/4/17. I also note that cars costing above £40 000 will pay a supplement of £310 a year for the first 5 years. That could encompass a few low-emission cars! I wonder how many models will be priced at £39 995? Presumably existing cars will still pay the old VED based on CO2 bands?

Yes; it only applies to new cars. One of our cars is a hybrid but we’ll be switching to a Nissan Leaf I suspect.

Surely that new policy will encourage the production and purchase of cars with zero emissions [0gCO2/km]. In the Summer Budget 2015, the Chancellor said “the new VED system will be reviewed as necessary to ensure that it continues to incentivise the cleanest cars”.

Surely that new policy will encourage the production and purchase of cars with zero emissions [0gCO2/km].

Well, it’s an ‘all or nothing’ approach, which means that instead of looking for the cars with the lowest emissions prospective buyers will be faced with either electric or anything else at all – diesel, petrol, coal – they’re all the same tax band, now. The original idea encouraged the purchase of cars with lower emissions but this doesn’t.

Electric cars will continue to be unsuitable for many, until they lick the range issues, so I suspect many will now abandon the move towards lower emission vehicles and go for whatever they like. In effect Osborne has turned the clock back on clean motoring.

I must agree that the saving of just £140 a year on VED is not sufficient to get people switching to zero emission vehicles, especially with petrol prices at their current levels and no sign of any significant reduction in electricity prices.

Given the forecast low generation capacity margin over demand I am surprised that such a policy is being introduced at this time.

I like the idea of a solid fuel-powered car. I’m not sure it would do much for pollution reduction though and is not recommended for people who keep their motor in a garage or wish to use multi-storey car parks!

Always fancied a steam engine myself :-)))

There is something nice and simple about steam engines, plus their ability to produce power from zero revs. I wonder if an electrically-powered flash steam generator and engine in a small car would have legs (so to speak). A problem with steam is, I believe, extracting its energy efficiently as it loses pressure in small installations. However as much electricity is generated by steam…………… 💡

my first car a hand-me-down from my dad when I was 17, Austin A40 (1956, 40bhp, 70m/h) 28mpg. my last petrol car, Audi A4 Quattro (2011, 215bhp, 150m/h) 27 mpg. I don’t recall every having a petrol car that did better than 30mpg. My present car BMW330d Xd (2014, 255bhp, 157m/h) 37mpg. Realistically the present manufacturers’ figures for the worst case comsumption are what you might get in real life. BTW I’ve lived in Germany for the past 25 years and that’s how you firgure it out. The German motoring magazine ADAC are running a similar campaign to Which? as well.

It has been clear for a long time that car manufacturers rig the fuel economy and emissions ratings of their cars in Europe. The German car manufacturers are particularly bad at this, but they have far too much control over the EU “regulators” and can do what they like. At last VW have been caught blatantly rigging the emissions tests in the US , but I suppose the EU/UK could not care less – too much money and political power has been invested in these poisonous diesel engines over here.
It is about time the CO2 issue gave way to the more immediate problems of particulate and NO pollution particularly caused by diesels. It is no surprise that rising asthma rates coincide with the rise in numbers of diesels.

It has been clear for a long time that car manufacturers rig the fuel economy and emissions ratings of their cars in Europe. ”
If you look at the real cause of this most of the blame lies with the EU regulators. They have allowed their NEDC test regime, that manufacturers must use to determine emissions, to continue to be imposed despite it being well out of date and inappropriate for modern cars and driving conditions.

I’m looking for a big headline in major newspapers where the top Which man or woman repsonsible for the Cars section comes out very strongly saying they and their readers have been denouncing this situation for a very long timne, and urging parliaments/investigators/regulators to act.

Thank you David, we have published a new convo about the VW scandal: https://conversation.which.co.uk/motoring/volkswagen-vw-diesel-car-pollution-emissions-mpg-scandal/

And we’ve put out a press release : http://press.which.co.uk/whichpressreleases/new-fuel-efficiency-tests-needed-to-rebuild-trust/

Richard Lloyd, Which? executive director said:

“Our research has consistently showed that the official test used by carmakers is seriously in need of updating as it contains a number of loopholes that lead to unrealistic performance claims. The car industry needs to focus on how to rebuild trust with consumers and we want to see the new fuel efficiency test introduced as soon as possible.”