Originally Posted by TerminatorX5

I use excel spreadsheet:

at fill-up i take the receipt, and write down the info from the receipt into the spreadsheet -

cost per gallon
miles at fill up
amount of gallons
total amount paid

after several fill ups a calculation is possible... therefore i know exactly how much my MPG is at each entry, can compute the total amounts of fuel, days, dollars, averages... The average cost per gallon came to $3.77, even though I had filled up for $4.30 a gallon and for 3.49...

I do not have the cost of operating the X, as the X is still in operation...

We had leased a 2011 335i xDrive Mpackage...

in 232 days we had it, the cost of operating that car came to $0.16 a mile in fuel cost, for 14,535 miles driven, and $0.46 cents a mile in amortization cost, and the grand total is $0.63 a mile including fuel, insurance, lease payments... a disclaimer, the car was returned with 3300 miles UNDER allocation for which there was NO refund, so the amount could have been a penny or two less, should all the miles be used up...
the daily cost for the car was $39.37 including the insurance, the fuel, the costs associated with lease - about the same as rental car of small size...