My Audi doesnt have an MPG computer so how do i calculate the mpg im getting?
Ive been buying diesel at £1.01 a litre of late. The tank hold just short of £61. I get around 580 miles out the tank when its running on the red for a few days - it may reach 600 but i dont chance it.
The tank is 61.5 litres in size
thanks
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Size of tank is irrelevant, as is red light and price.
1. Fill tank, zero trip odometer.
2. Fill up next time - divide number of litres by 4.54 (litres to gallon) - that gives gallons used.
3. Divide mileage on odometer by number of gallons = mpg.
4. Repeat several times for different driving conditions to get average mpg??
Use calculator on your mobile for calculations.
I'm sure someone will come up with an easier method!!
Phil
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Forget all that!!!
Fill it up to the neck and record the mileage.
Do a couple of hundred miles or so - the more the better.
Fill it up to the neck again.
Write down the mileage again and the amount of diesel you put in.
Work out the mileage you have done between fills.
If you want the figure in miles per gallon multiply the litres you have put in on the last fill by 0.22 to give gallons.
Divide miles done by gallons and you have the miles per gallon.
Hope this helps.
FTF
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I knew someone would come up with something more complicated!! or the same!!
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1. Fill fuel tank to the brim
2. Reset trip meter button, or make a note of the total mileage of your car
3. Drive around as normal
4. When you feel the need to refuel, fill up to the brim again.
5. Note down the amount of fuel just put in the tank, and the current mileage of your car.
6. At this stage you know the mileage done between fillups, and the amount of fuel that you put in. EXAMPLE: 500 miles & 45 litres.
Since there are approx 4.5 litres to the gallon, this means that you put in 10 gallons of fuel
7. 500 miles divided by 10 gallons = 50 mpg
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43.6. >>
Jamesh266 - top marks for actually aswering the OP's GCSE typical question [i.e. contains insufficient information or vague or imprecise data ]. However, deduct 50% for not showing your workings - as the assumptions in arriving at your precise 43.6 figure are not clear!
;-)
all other respondents - full marks for telling audiA6tdi how to do his sums, if only he knew how to do sums; but award yourself zero marks for failing to do his calculation based on information he had supplied, clearly hoping that you would do the sums for him.
audiA6tdi - join the rest of Britain for lacking basic arithmetic skills.
;-)
My own sums:
I say that based on the data supplied, audiA6tdi gets roughly just under 10 miles to the litre [or say under 10 miles to the £ using his current diesel prices].
Say that due to the imprecise nature of the data supplied, it is convenient to use a rounded conversion factor of 4.5 or 4.6 litres to the gallon [waste of time to use accurate figures to multiple decimal places 4.546xxxx ...... ]
That means audiA6tdi is averaging roughly in the region of 40 to 45 miles per gallon, give or take a few miles.
Edited by jbif on 03/07/2009 at 08:29
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As other posters have said, fill to the max drive for a couple of hundred miles then fill up again and note the litres needed to fill up then the mileage
once this is done then you can enter your figures in here :-
www.torquecars.com/tools/uk-mpg-calculator.php
I have always used this site and found it to be acccurate.
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Use the same pump to fill up each time when using this method. I find that different pumps cut out at different points.
Only my two pennyworth....have a nice day.......MD
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www.torquecars.com/tools/uk-mpg-calculator.php
What a good site. It's in the Bookmarks already. Thanks....MD
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jbif
We don't know how accurate the speedo is, a non standard wheel / tyre combo would affect the speedo reading................................You did'nt ask, tut, tut
jamesh266 used the data given and produced a better result than you
"40 to 45 miles per gallon, give or take a few miles"
So if we presume a few miles to be 3, so 37 - 48 being your answer?
Can anyone else produce a more vague answer from the info given.
[pedantic mode off]
;o)
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Can anyone else produce a more vague answer from the info given. [pedantic mode off] >>
;-)
Dox:
Thank you so much, you have made three of my points.
Although it is very likely that you may not realise which points, and it would probably be a waste trying to explain to you as I guess that my original post includes a vague reference to a fact that has hit close to home, if not precisely on target.
p.s. another two points,
1. why do you assume "few" means 3, and
2. why do you assume that the "give or take" applies at the limits in the direction you have chosen?
;-)
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1. why do you assume "few" means 3 and
I presume few means 3 or more as anyone else would
2. why do you assume that the "give or take" applies at the limits in the direction you have chosen? ;-)
To imply give or take to be between 40 and 45 would just be nonsense...................
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The only suggestion I would add to what fredthefifth says is that the calculation should be carried out over periods of one month. Record the amount bought and the odometer reading every time you fill up, and calculate at the end of each month. Expect there to be a variation from month to month and from season to season. Both your driving style and journeys, and the weather, will affect your mpg.
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Alternatively, register here and it will work it all out for you.
www.spritmonitor.de/en/
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Brim-to-brim is a very poor way of doing it unless your petrol gauge is very poor. Much better to record the mileage when it reaches three-quarters full on the dial. Then zero trip meter; drive; fill up; record mileage when next reach three-quarters full. And then calculate.
(Agree with jbif, by the way; anybody answering 43.6 to OP's post really doesn't understand.)
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£61 divided by £1.01 = 60.39 litres
60.39 litres divided 4.54 = 13.3 gallons
580 miles divided by 13.3 gallons = 43.6MPG
Pick fault with that
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Pick fault with that >>
As subtle hints are not enough, may I point you to a website which summarises the rules of simple arithmetical operations [adding, subtracting, multiplying, dividing].
www.usca.edu/chemistry/genchem/sigfig2.htm
"When multiplying or dividing numbers, count the NUMBER OF SIGNIFICANT FIGURES. The answer cannot CONTAIN MORE SIGNIFICANT FIGURES THAN THE NUMBER BEING MULTIPLIED OR DIVIDED with the LEAST NUMBER OF SIGNIFICANT FIGURES."
Note that the "SHOUTING" is as is on the website, and not mine.
So taking the data provided by the OP at face value, your calculation should read:
All operations in one go
( 580 / ( (61 / 1.01) / 4.54 ) ) = 44 mpg *
or doing it line by line as you did:
£61 divided by £1.01/litre = 60 litres
60 litres divided 4.54 = 13 gallons
580 miles divided by 13 gallons = 45 MPG *
[ * least number of significant figures in data = 2 ]
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jbif, if I'd have done it that way you or others would have picked fault, I used the figures given.
How come the 45MPG that you've now arrived at isn't smack bang in the middle of your previous 40 - 45 MPG? (plus or minus a few of course)
OP wanted a laymans terms explanation of how to work out his MPG, you work on the principle of if you can't blind them with science baffle em with BS. OP should now be able to do the basic calculation himself without the patronising comments from you.
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in reply to Dox:
First, don't worry, you can't always be right.
jbif, if I'd have done it that way you or others would have picked fault, I used the figures given. >>
Not so, I would have applauded your common sense; - nay, not so common sense.
How come the 45MPG that you've now arrived at isn't smack bang in the middle of your previous 40 - 45 MPG? (plus or minus a few of course)>>
Because 45 is obtained using the OP's optimistic inaccurate data, and the 40 is obtained using my own pessimistic assumptions. The final figure has caveats built in which were alluded to in my OP and the result is an estimate = "40 add few" or "45 minus few". Substitute your own values for "few"
OP wanted a laymans terms explanation of how to work out his MPG, >>
If OP is that anal about mpg figures, perhaps he should learn the importance of providing accurate data.
you work on the principle of if you can't blind them with science baffle em with BS. >>
Some more science and BS to baffle you. The vast majority of odometers overread mileage. Indpendent tests have shown that the vast majority of petrol/diesel pumps supply more litres than you are charged for. Independent tests show that nine our of ten cats use platinum as a catalyst.
OP should now be able to do the basic calculation himself without the patronising comments from you. >>
Good for you. Glad to have been of help to you and the OP [as you are now speaking on his behalf].
Normal service will now be resumed.
Edited by jbif on 03/07/2009 at 14:31
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You've learned me nothing I did'nt already know;o)
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Alternatively divided 600 by 61.5, multiply by 4.5, result 44.3 mpg.
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Pick fault with that
should be 4.55 1 gall = 4.546091.....
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>> Pick fault with that >> should be 4.55 1 gall = 4.546091.....
20 years ago when I was a company car driver I was paid a basic fuel allowance and claimed back anything over and above at the end of the month, I still use the same figures and method to this day, it was good enough for the company auditors and its still good enough for me.
It makes a whole 0.1 MPG difference
Next.................................................
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Brim-to-brim is a very poor way of doing it unless your petrol gauge is very poor. Much better to record the mileage when it reaches three-quarters full on the dial. Then zero trip meter; drive; fill up; record mileage when next reach three-quarters full. And then calculate. (Agree with jbif by the way; anybody answering 43.6 to OP's post really doesn't understand.)
What drivel
Fill a vessel whatever shape it maybe, empty some out of said vessel and refill measuring as you go stopping at the same datum mark.
Google archimedes
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(Agree with jbif, by the way; anybody answering 43.6 to OP's post really doesn't understand.) >>
Mapmaker, many thanks. But then I do know from your past posts that you do understand the meaning of figures beyond doing simple sums. Enough said.
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Calculating the fuel consumption of a motor car is a simple sum.
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The most accurate (long-term) and foolproof way is to do it graphically. Just record quantity bought and mileage every time you 'fill up' (I never do) and plot those figures, miles across the bottom (X-axis) and litres (gallons if you must) vertically (Y). Rule a best straight line as close a possible to all the points and divide X by Y where the ruled line crosses the edges of the paper.
This eliminates misleading calculations caused by points 'off the line'. And if the line looks like a curve, some fault may be indicated in your motor ...
Edited by Andrew-T on 03/07/2009 at 11:16
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Calculating the fuel consumption of a motor car is a simple sum.>>
Or not, according to this thread. [that is just for doing the sum].
Consider also the accuracy of instruments to gather the data, and the design of fully replicable robust experiments using exhaustive scientific controls to test the results.
Someone may already be trying to do so, I think, because I have heard of something referred to as "official fuel consumption"* figures:
"official fuel consumption" means, in relation to a model of passenger car, the fuel consumption figures for that model measured in accordance with the provisions of Council Directive 80/1268/EEC of 16th December 1980 and contained in the relevant EC type approval certificate or EC certificate of conformity, except that where a model comprises more than one variant or version it means the highest such figures for any of those variants or versions
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>>Brim-to-brim is a very poor way of doing it unless your petrol gauge is very poor<<
Brim to Brim is the only way to do it accurately - but over multiple fills. Calculate individual, last 5 fills, and total running average if you really want to be anal.
Have you ever seen a fuel gauge that can be regarded as 'accurate' or even 'repeatable' to the accuracy that you are demanding?
Why I have replied I do not know! When I saw the original post I swore to myself that I would not be sucked in for risk of making offensive comments about the lack of arithmetical intellect of apparently intelligent people. The way the thread has gone has only confirmed my beliefs!
p
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"Brim-to-brim is a very poor way of doing it unless your petrol gauge is very poor" = tosh
Brim-to-brim over five fill ups will eliminate all the significant errors.
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I simply put the miles travelled, cost per litre and the litres used into my iphone application and it works it out for me for each vehicle :)
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Sad as it may seem, I kept a constant watch on the fuel consumption of my last Accord over the 4 years I owned it, recording mileage and fuel every time I filled up. Over that period the consumption varied from 27 to 37mpg, with an average of 33.2mpg.
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