Shouldn't the average price per gallon be given by (All-time amount spent) divided by (All-time gallons consumed)? This is how I calculate average PPG in my spreadsheet, but it is off by a penny from Fuelly. What's up?
Look at Little Bertha's page (the Saturn SL2). All-time gallons consumed is 3208.23, and all-time total spent is $8,530.78. So shouldn't the all-time average price per gallon be given by $8,530.78/3208.23 = $2.6590 = $2.66 to the nearest penny? And if so, why is the all-time average price per gallon under "Cost Analysis" showing $2.67?
IOW, a straight average price per gallon rather than a weighted average price per gallon. Gotcha. Interesting that the two are so close together, though I suppose that might be different if I had more partial fuel-ups.