Life Time MPG Average

I have to calculate mine because I did not think to leave the Trip B setting alone when I first got my car. A lot of people on here have never reset their Trip B display so this is their real time lifetime averages.

 

I use an excel spreadsheet modified to show the information I want it to calculate. I add other notations like oil changes, tires, and parts to the side of the spreadsheet. The information is next to the closest fillup which tracks the date and mileage. I made a column for the cents per mile also.

I believe it started as a sample spreadsheet in the program. There is no lifetime average in the MFD. If you don't reset the mileage each fillup, it will reach a point where the mpg will not change due to the amount of data.

I know some of the members post their numbers and log them on another website. Check their posts and see if that might be what you need. Jerry

 

I just posted a gallery showing my lifetime MPG. Like the others have stated, I used a spreadsheet to collect my data to generate these plots. Every time I filled up I wrote down the date, time, temperature, odometer, miles and MPG shown the display, and the gallons and cost from the receipt.

After 170000 miles when I sold my 2004 for a 2010, I had an average of 49.81.

Attached is a plot of my MPG data. More plots can be found in my 2004 Prius gallery in my profile.

Peter

 

IMO, only two numbers count: the miles driven & the gallons pumped. The computers will continue to compute & hold the lifetime average until they are reset or lose power. If you rely on the car's numbers then record them elsewhere before your data is lost.

 

i track mileage driven, amount of gas put in, amount of money taken out (of my pocket) and what the computer says i should have gotten.

i also separate summer and winter #'s since there is a pretty drastic change.

 

Each time I fill up I record the odometer reading, the mpg and average mph from the MID, and gallons and cost from pump receipt. I enter these in a spreadsheet that calculates actual mpg, compares to MID mpg, calculates mpg error and percent error. I keep a running average of all of these calculations. I also enter the average temperature during the time between fillups. I then trend the calculated mpg, the MID mpg and the average temp.

 

I am sure what he means is that when you have say 3000 miles in memory, or much more, it will kind of stay the same as that is what is averaged against your current performance, that is. The more miles the less real response you will get. Try to average say a 50mpg average on 10k miles and the next tank is 48 for 400 miles.

 

What kind of difference are you seeing between the MFD and the calculated mpg? My spreadsheet shows the MFD on average reports "high" by 1.4mpg per tank. Of course there are variables introduced into the gallons used amount since I use different gas pumps and gas stations.

 

I am seeing the MID is about +3 mpg high on average. This appears to be about normal for the 2010 according to other posts on this subject.

 

2010's have demonstrated a greater difference between computer and pump for mileage. i am trying to correlate the difference by when one took delivery. not many here exhibit as wide a difference as i do on my 2010 which i received mid-May.

it does appear that latter builds have narrowed the gap considerably. now on my 2006 and 2004, the differences were both just over a mile per gallon (see sig) so relatively accurate

 

My old 2000 Insight (261K, lmpg=62) had a lifetime mpg along with trip A and B. I guess my 2010 Prius has no such thing, ay least I can't find it . I guess the idea of using trip B as a lmpg will have to do, unless I am missing something.

 

As opposed to logic, I somehow started using trip A as my Lifetime guage. I didn't start till about 2100 miles, I have about 10500 on it now. My MFD is consistantly 2.1 mpg generous. So, for about 8400 miles the display is showing 54.4 (coming up since winter finally ended) 54.4- 2.1=52.3 mpg for 8400 miles. I obviously use trip B as my trip meter. Hope this helps.
Tony Renier

 

Over the lifetime 21,500 miles on my 2007 Prius, my spreadsheet calculated average is just over 48 mpg. The averaged mpg displayed by the MFD is about 2.5% better, which would calculate to about 1.2 mpg optimistic.

 

Which confirms the margin-of-error is greater than real-world variation. I've witnessed that same thing on all 3 generations.

In other words, after enough distance, the display of lifetime doesn't actually indicate much anyway.
.

 

Did you mean the trip A does not roll back to zero after 10K miles for the 2010 Prius?

 

If you are counting in this information, consider recording it before each service trip.

Some techs don't know how to reset the service reminder without also resetting Trip A & B.

 

My running average is 44.