calculated vs. computer MPG - Please post your results

The MFD will update the display of average fuel consumption also when you are not moving, whether you are in park or drive. Essentially the MFD does take into account fuel consumed from the ICE in all conditions.
Moreover, pumping to the brink or stopping at the first stop, will change the calculated percentage wrt the MFD, but it will also vary from time to time.
In EU, from first stop to "full to the brink" (you see gas in the tube), is about 0.5L/0.125gal or maybe a bit more (I think it depends on how the pumps are calibrated). Over 30-35L/8-9gal, that is about a 1-2% difference. This also why likely my average is about 6-7%, instead of 5-6% - I always fill it up to the "brink", i.e. I never stop at the first stop, but add another couple.

OK, my car is now 2 years old!

Over 2 years and 44970 miles tracked.....

Displayed MPG = 62.8
Calculated MPG = 59.4
% Difference = 5.8%

I don't know how you do it but those are awesome numbers, bru.

Last tank:

326.3 miles
Gas used: 5.675 gal
Displayed: 61.3 mpg
Calculated: 57.50 mpg
Error: 6.6% or 3.8 mpg

Price: $4.129/gal !!
sonofabitch!

Second tank:

508.3 miles
Gas used: 9.404 gal
Displayed: 56.5 mpg
Calculated: 54.05 mpg

Very first fill up:

said 1 mile to fill up on display
487.4 miles
Put in tank: 10.075
Displayed: 49.6
Calculated: 48.4

Most recent fill-up in hilly Connecticut
MFD = 56.3
Calculated = 53.2
MFD vs. Calculated = -3.1
% Error = 5.77%

I agree, love some of the ultra high mpg's that some get. If I only do my standard commute I might get 55-57... But that is not realistic in real life.

So far very happy with the about 5% difference between the MFD and computed. Did two in a row at 51.2mpg calculated. Results and some details here: The Grey Ghost (Toyota Prius) | Fuelly

Join us on Fuelly so we can compare notes....

My 2011 Prius the computer readings were off by 2.2 to 2.8 mpg higher than actual.
My 2012 Prius I just filled up (1st tank) and it is off by 2.9 mpg.
I calculated 44.7 mpg, computer read out 47.6 mpg.

Miles: 253.9
gal's used: 4.779
MPG indicated: 56.1
MPG calculated: 53.128

Costco reg gas with 10% Ethanol

My wife drove about 70% of the time and
she does not drive for mpg's.

A month ago it would have been 46-48 mpg
calculated.

Temps now in the 50's with dry roads the last
few days makes a 10% difference in mpg's.

3rd tank
Non Ethonal
Miles:520
Gallons: 9.200
Actual: 56.5
Computer 58.8
This time I went past the first click of shut off & added a few more just to see how far off the computer would be. It was off but wouldn't have been off if I had shut off at 1st click about 8.9 gallons. Well that is what experiments are about. Duel foot print on this tank since DH had a crash with the Subie.

Last time I tanked it stopped at exactly 40L - I topped off at 40.98L. I made the calculations and the former case the error would have been 6% over 1051km (I half-filled 2 times before being able to do a complete full-up). In the latter case, it is a nice 7.48%, that is 1.48% difference...

833.2 miles (two tanks) was not reset after first fillup (424.9 miles/
58.8 indicated / 55.849 calculated /90% highway.)


15.631 gallons

Indicated: 56 mpg

Calculated: 53.304

85 % highway 40 - 70 mph

Reg Gas with 10% ethanol


Tires: 195x65x15 Michelin Energy Saver
with 44 psi in all four tires

Ditto! No AC and 44 PSI in the 15 inch tires.

This car seems to do better than the 2009. I am getting a 2012 in 2 weeks.

Well I just filled up for the first time. This was on the dealer tank.

Flashing fuel bar and only took 9.8 gal. (I had about 97 more miles of gas.)

MID - 49.0 mpg
Calc - 48.5 mpg
Deviation -1.02 %

About 35% city; temp 55-70 F; tires ~40 psi.

Very happy, because I have been learning all week.

SORRY: I started my own thread before seeing this, so above I cut and pasted.

:deadhorse:

ITS $6.60 PER GALLON HERE !!!

:canada:

It is 7.86$ gallon here.... and 9.50$ in Italy (Tuscany to be precise)...

Last tank:

524.0 miles
Gas used: 9.118 gal
Displayed: 61.0 mpg
Calculated: 57.47 mpg
Error: ~ 6%

Well, my philosophy is that there's always going to be someone worse-off than you, but you still gotta complain from time to time

P.S. What in the same of sweet baby jesus are those smiley faces doing to that poor animal? I didn't know you Canadians were so kinky.