Real world mpg?

[Saucebox]

I'd be most interested to hear from as many members as possible in answer to the above question, please.

Separately, what's the consensus of opinion as to the percentage inaccuracy of the claimed screen computer mpg figures?

[dfconnolly]

If you download the “Spritmonitor” App you can see what real mpg figures are being achieved by Jazz owners.
As usual, the infotainment figures can be 10% higher than the true mpg!

[Jazzik]

Check on https://www.spritmonitor.de/en/overview/18-Honda/1293-Jazz_Hybrid.html?constyear_s=2021&minkm=10000&powerunit=2

My real mpg over 16 months you see down here.
 

[Kremmen]

If you dig around the Mk4 section there are plenty of existing examples of actual MPG by road type.

[nowster]

Separately, what's the consensus of opinion as to the percentage inaccuracy of the claimed screen computer mpg figures?

In my experience the fib-ometer is about 5%-10% on the optimistic side.

[Lord Voltermore]

At least the 'fibometer' is consistent.    If the computer says 66 mpg one trip,   but 56 mpg on another  You know your speed, driving behaviour  ,weather conditions etc are  now  10 mpg less favourable.       I dont need to know the figures are really   64 mpg and  54 mpg before I will  take action to reduce it. Ultimately the fuel costs what it costs for the distances I chose to travel.   I think I have averaged about 67 mpg, mixed driving from new. Fibometer.  If the reality is a few mpg less I am still more than happy.    Indeed the car is such a pleasure to drive I'd even be happy if it had little or no  mpg advantage over conventional cars.   

If comparing the advertised mpg for two different cars you may need to know you are comparing like for like.  IMO the computer figure is closer to reality than some hypothetical mpg  figures claimed in adverts  and reviews.

[stiggysawdust]

Quite normal at this time of year with extra use of heating etc,

[ColinB]

I've said this before but I'll say it again: there is little point in comparing mpg figures with someone else's. There are too many variables - the car itself, loading, speed, traffic conditions, weather, driving style etc. The only value in the mpg calculations, whether from the car's computer or brim-to-brim  measurements, is to monitor your own and your car's performance and take action if its not what you expect. It doesn't matter if the computer gives a slightly different value to any other method, it's just a very convenient way of keeping an eye on what's happening.

[Nicksey]

All I know is that to my previous Renaults, which all had the TCE 90 engine (which I always thought very good) was that I am getting about 20 MPG more on average. Which is excellent in my view.

[peteo48]

I use spritmonitor like several others on this site. In short it enables you to compute your real mpg by filling up to full (first click on the pump) and working out the mpg from there.

I don't know why but 4 mpg optimistic is what I have found on a number of cars now. It's astonishing how often it is 4 mpg. Very occasionally it will be a bit less than 4 and sometimes a bit more.

Knowing this I don't know why I still use the manual calculation - if I knock 4 mpg from the what the car says I am about right.

[dfconnolly]

Check on https://www.spritmonitor.de/en/overview/18-Honda/1293-Jazz_Hybrid.html?constyear_s=2021&minkm=10000&powerunit=2

My real mpg over 16 months you see down here.
 

So looking at your total consumption versus mile done Spritmonitor show’s overall average of 68mpg……excellent!

[Jazzik]

So looking at your total consumption versus mile done Spritmonitor show’s overall average of 68mpg……excellent!

Alas... I (only  )  read...

[Lord Voltermore]

My 'fibometer' reading was about  68 mpg over 10000 miles of mixed driving over 14 months.  .  Just noticed I must have accidentally reset the trip and its now  reading 63.9 mpg  over 1000 miles . Most of those were done on the motorway in freezing temperatures in December.   Some stretches were speed restricted to 50 mph, or 90 kph  (55mph) which will have helped mpg quite a lot.    Even allowing for the computer being a bit optimistic I am happy with that result in the circumstances. 

I believe the Yaris Hybrid has a slightly better published  mpg figure  .But I thought  the Yaris felt like a smaller class of car.  More cramped. The Jazz feels roomier  with a much better view.  Almost like sitting in a bay window compared to the Yaris.  I suppose the Jazz's boxier shape adds to wind resistance, but for me the benefits outweighed  a slight fuel penalty. 
Much as I love my Jazz when the times comes to replace it I will probably test drive a few newer hybrid alternatives to see if any now  better suit my needs. Looking at mpg figures can only tell you so much. Actually Honda can be quite conservative in things like claimed 0-62 time.  Reviewers often  improved on this  by a second or so in tests.  Can other makers say the same? 

At present a full EV is not an option for me. ,  unless they, or my driving needs, change significantly.  Which they might.

[Marco1979]

This is my second winter with the Mk4. I notice a decrease, mostly because of being more familiar with the possibilities: using the heated seats more and ventilation less. Also when the engine is cold and I have to drive in town with many traffic lights, I switch off the fan completely.
I now manage to stay around 4.2 to 4.5, while last year it was 4.5 to 4.8. In mpg it would be 58 last year and 61 now. Total average is 68 or 4.15. 15% less than the Mk3 (both 1.3 and 1.5 cvt got about 60 mpg). Happy  !

PS: calculated based on distance and volume, fibometer is a bit too positive (0.2 or 0.3 l/100km)