How many MPG am i doing?

[Acheron]

Terrible at maths and my calculation is coming up to 17 which i dont think is correct.

£40 according to the trip computer was going to get me about 200 miles, but i disagreed with this. I noted the fuel level and reset the trip on the mileometer, and its pretty much about the same place, with 140-150 miles travelled.

So £40 is getting me about 140 miles.

Is this right at 17 mpg?

[DavidHM]

£40 @ £1.30/litre = 30.77l = 6.78 gallons as there are 4.54 (recurring) litres in a gallon, i.e., 1l = 0.22 gall.

So that means you're using 6.77 gallons to go 140 miles.

So your mpg is 140/6.78 = 20.68 mpg. The more the fuel costs, the less mpg you are getting in this scenario as there are fewer gallons to £40.

[Mr Will]

Fill the tank to the brim, reset the odometer, Drive.

Fill the tank to the brim again. Divide the number of litres by 4.54 to get the number of gallons, then divide this number by the number of miles on the odometer to get MPG.

Doing it in pounds using the gauge is way too vague to be useful.

[james_gt3rs]

22mpg by my calculations. Maybe you did American mpg?

[Acheron]

Cheers, i got a C in GCSE maths and that was about 8 years ago, never touched it since

[NiceCupOfTea]

£40 of petrol @ £1.40ppl is 40/1.4 L = 28.6 L

28.6L = 6.3 gallons (4.54L in a gallon)

Therefore, 140 miles to 6.3 gallons, so 1 gallon will get you 22 miles.

If you want a formula:

MPG = miles covered / (( [cost of a tank] / [price per L] ) / 4.54)