MPG Calculation Help

[500E]

Hi all,

Not being the best at maths I need some help with calculating accurate MPG...

Bought fuel for £25.00 - Shell V-Power 22.96 Litres

I think the price was 108.9p per litre but not sure (reciept does not show it?)

This fuel gave me around 175 miles of motorway & town driving (70:30 respectively) and not driving slowly either before it went onto red again (filled up when it was on red).

Whats the accurate MPG? The car is a 2.0 GTI.

Thanks all.

 

[stevesey]

175/(22.96/4.54) = 34.6

Accuracy of course depends on how the 22.96 was measured - was that full -> full usign the same pump (so same cutout point).

 

[BTB 500]

Also the mileage ... "around 175 miles"?!

You can't get an accurate MPG figure without accurate miles covered and accurate fuel used.

 

[500E]

Well, the odometer was 175miles from being red when I filled up and back to red.

The 22.96 litres was taken off the receipt.

So I guess 34MPG is fair?

 

[G.O'Rilla]

Keep the receipts, add them all up over several fills and then do the calculations....... that way you eliminate any variations in driving conditions and get a more meaningful result. Being a bit picky, I keep it all on a spreadsheet for every car. Goodness only knows why!

 

[stevesey]

Well, the odometer was 175miles from being red when I filled up and back to red.

The 22.96 litres was taken off the receipt.

So I guess 34MPG is fair?

It's best to do mpg from brim to brim (full tank - preferably using the same pump, but I'm not that obsessive) trying to do it from the gauge position will be very error prone.

As G.O'R says keep a spreadsheet - then you can do, last fill up, average over last 4 fill-ups etc.

 

[MrT]

Or use Spritmonitor - http://www.spritmonitor.de/en/

 

[yachtman]

Or use Spritmonitor - Mileage Calculator and Vehicle's Costs Analyser

another user of the above

 

[hawk20]

Hi all,

Not being the best at maths I need some help with calculating accurate MPG...

.

The simplest way is called the tankful to tankful test. Fill the tank. Set the trip to zero. Drive till ready to refuel. Fill the tank again. The amount of fuel taken to fill the tank is the amount you have used to do the miles shown on the trip meter.

Say you have done 350 miles and have used 50 litres. Divide the 50 litres by 4.55 equals 10.989 gallons.

350 miles divided by 10.989 gallons equals 31.85 miles per gallon. Or approx 32 mpg.


A gallon is equal to 4.546 litres -or 4.55 is accurate enough for normal use.

 

[wemorgan]

Or use Spritmonitor - Mileage Calculator and Vehicle's Costs Analyser

another user of the above

I've signed up too now. Is there a way of finding all MBClub members who have signed up and link the mpg in their signatures?

 

[JonMad]

I saw that sprintmonitor on christopherwk's sig earlier. Does he ever have a day off driving?!

If it does all costs, not just fuel then it might replace my spreadsheet and provide some amusement at the same time.

 

[wemorgan]

I saw that sprintmonitor on christopherwk's sig earlier. Does he ever have a day off driving?!

If it does all costs, not just fuel then it might replace my spreadsheet and provide some amusement at the same time.

Yes you can add purchase costs, servicing costs and many others too.

You can also set up reminders on specific dates and mileage for servicing, tax etc.

 

[JonMad]

Does it appear if I make another post?

 

[wemorgan]

Does it appear if I make another post?

26mpg!.....you're the yin to my yang

 

[JonMad]

22.7. Strange, Excel makes it 20.5 using 4.546 litres per gallon. Hmm.

heh heh - all costs to date added

 

[wemorgan]

22.7. Strange, Excel makes it 20.5 using 4.546 litres per gallon. Hmm.

Is your Excel spreadsheet calculating the average per fill-up or the average over the whole distance?

eg.

fill 1: 300 miles and 30mpg
fill 2: 30 miles and 20mpg

average per fill = 25mpg
average over distance = 29mpg

 

[JonMad]

Fixed it - the website defaulted some of the mpg readings to 'invalid' so was calculating it's average from too few values.

 

[wemorgan]

Good to hear. All we need to do now is convince more members to sign up.

It should at least satisfy those threads: 'what efficiency can I expect from a.....'

 

[hawk20]

Hi all,

Not being the best at maths I need some help with calculating accurate MPG...

Bought fuel for £25.00 - Shell V-Power 22.96 Litres

I think the price was 108.9p per litre but not sure (reciept does not show it?)

This fuel gave me around 175 miles of motorway & town driving (70:30 respectively) and not driving slowly either before it went onto red again (filled up when it was on red).

Whats the accurate MPG? The car is a 2.0 GTI.

Thanks all.

This is not an accurate way to do it.

Best method is to fill the tank. Record the mileage (or reset trip). Then drive until reasonably low and refill the tank. However many miles you have done, you know that you used exactly the amount of fuel needed to refill the tank in order to do those miles.

Convert litres used to gallons. Just divide by 4.55 for reasonable accuracy on the gallons of fuel used.
Divide the miles done by the number of gallons e.g 300 miles divided by 10.0 gallons = 30 mpg.

 

[christopherwk]

I saw that sprintmonitor on christopherwk's sig earlier. Does he ever have a day off driving?!

Ha ha, no! It's my job! - hence Steve mentioning in another thread I was on 178,000 miles at the last GTG a few weeks ago! [find out my current mileage by clicking on my sig!]

It's certainly useful if filled out accurately, looking at the different MPG's you get from different fuels (i.e. normal/V-Power/Ultimate), and type of roads.

However, the metric/imperial figures are all over the place when you click on someone else's sig - the mileage (if entered) is in miles, but the distance/trip meter is in kms, while the total cost is in Euros, and the fuel used is in litres/100km!

Log in to your own account and the figures are more in a more user friendly form of £, mpg and miles.

For other costs (servicing/tyres etc) I use the blog function on Pistonheads My Garage (since I only started using Spritmonitor a few weeks ago), where it will calculate pence per mile taking everything into account, but you'll need to enter the average mpg and price paid for fuel. christopherwk's Mercedes* E320 CDi* Avantgarde *(2003)