I just added my fillups to the mileage database, but I wasn't sure whether I should use the display mileage (which seems to be a bit optimistic in the 2004 Prius) or the actual calculated MPG.

Thanks!

If you want the most accuracy then enter the calculated amount if the dispay is not correct.
In my case it is pretty accurate.
Thanks

I guess I'll go back and change it. If I'd been able to use the same pump all the time, it would probably be a little better....

I've been using the display, just because it's easier. In the end, it will only make a difference of 1-2 MPG. If 1-2 MPG makes the difference in someone's car purchase, they're either psycho or driving a truck :P

I hoped that everyone was calculating the numbers (isn't it called the Real Mileage Database?). The display in my 2000 Prius is always 6-14 % too optimistic. It is not only optimistic, but also varies a lot. Don't know how it works.

6-14? Wow! Real as in not "CBS 35" or "EPA 60" averages. There is no possible way I can mandate how the hundreds of people using the system are going to calculate their averages. If I could force everyone to record their odometer and fuel amount numbers, I would. It just isn't going to happen, though.

What I've seen from the members on GreenHybrid so far, they seem to be willing to make an effort when it comes to mileage... :P

But I can see your point, and I guess you know your members a lot better than I do. How about recommending to find out the average deviation on the display, and then recalculate before entering the data here? In my case I would take my display mileage of 48 and take away the average 10 % to get 43.

Too hard :) In today's world, quantity rules over quality. However, there are still things I can do. I plan to add a few more features to the database when I have time. Of these would be allowing the member to select whether their measurement is by display or calculation. Another is the average % speed over/below the limit.