ahhh i see, yeh i shall do that in excel right away. but a question, what do you reckon still tho? filling up the fuel weekly regardless how much fuel left you got, or use up till the last bar of fuel left then go fuel up? Fill up when it is cheap. Regardless of how much fuel you have left. I filled up on Wednesday but since the price has been pretty good I filled her up again today. Your car isn't going to go 'Oh damn. crolladx doesn't have much fuel left and fill day isn't for another 5 days, I am going to consume less fuel to compensate', so just fill when the price is good.