I'm on my very first tank of gas in my brand-new hybrid. My gas gauge is between one-half and one-quarter empty, and I have 433 miles on the car. My question is...do most of you calculate your own gas mileage (number of miles divided by number of gallons it takes to fill), or do you just use the number on the dashboard display?

 

I track both and I am finding that the displayed MPG on my 2 month old Honda Civic Hybrid is actually a bit under the physical miles/gallons-in-tank calculation. Don't be discouraged by a lower than expected mpg with you new car, it'll steadily improve as it gets broken in. My Honda started out at 47.5 and has now improved to 50.4

 

I also use both. I'm up to 25 tanks and have found the mfd readout is about 1 1/2 to 2 mpg higher than the calculated. I have been using the same pump to fill from when I bought the TCH a year ago. Although I did recently switch from phillips 66 to a larger Texaco station.

I did take a couple of 1" (3/4" actual) thick short boards with me this one time. I placed them under the low side (passenger) wheels of the car. My car was level as could be. Still the tank fill calculated reading was just over 1 mpg lower than the cars readout.

I do fill with the nozzle on low and use the auto lever setting. I let it shut off once then I remove the nozzle.

My guess its like all cars speedometers. You drive 60 and you actually going 58 miles per hour. I also found at 35 mine is really going 34.

I work to get my best mpg by using the mfd readout. Overall tank mpg, I only trust the calculator method as to be accurate. I find it's much more accurate if you use the same gas pump ever time.

 

I calculate my gas mileage and compare it to the display. As with the other responses my display is usually about 1.5 MPG higher than the actual computed MPG. Using the actual calculated MPG isn't as good for "bragging rights" as the display but I want to know the real MPG.

I usually refuel at the same pump and commit the "sin" of topping off my tank to the same level every tank so I know my results are fairly consistent.

If you haven't already please consider enrolling your car in the Real Hybrid Mileage Database linked in my signature. I think it's a good tool for tracking your MPG and it lets others see the real world MPG results owners are achieving.

 

The results on that page aren't what I would call "real world".
Just guessing, but 15% of TCH owners are fanatics (like us) and go out of our way to achieve improved mileage.
The other 85% of owners are 'normal' people who just get in the car and drive. They don't fixate on the little things, such as tire pressure and achieving Stage 4 as soon as possible.
IMHO, the page should not be looked at as a cross section of the TCH driving population.

 

True. It's kind of like putting a poll on AVSforum.com and asking them how much they spent on their home theater setup to get an "average" cost of TV's. The number will be very skewed from reality.

However, it's still a great source of information and shows people what's possible. I figure the lowest MPG's are worst-case scenario, and the highest are to be taken with a light-weight, overinflated grain of salt.

 

I also keep track of both and like others have said my MFD is usually 1.5 MPG higher than calculated. There have been a couple of times it's been spot on but that's very rare. I just filled up my tank yesterday and my MFD showed 41.5 MPG and my calculation showed 41.6 MPG.

 

My TCH is within 2-3 tenths of actual, but both Lexus vehicals always read 3-4 MPG higher on commputer than actual fill (I suspect it is to make the driver feel like they are getting way better than they are) of course the fuel never stays in the Lexus long enought for it to properly compute lol!

 

I also see variation with the mileage on the car's multifunction display being slightly higher than what I get by dividing odometer miles by gallons purchased.

There are a couple other threads that discuss the relative (in)accuracy of the speedometer (reading high) and odometer (reading low). Comments have been made by people that believe their odometer reads about 2-3% low, and that by adjusting the mileage upward by that much makes the calculated and displayed mileages match much better.

Here are my results to date, having owned my car about 6 months. Miles = odometer miles, MFD = multifunction display tank mileage, Calc = hand calculation from odometer miles and gas purchased, Variance = difference.

Miles MFD Calc Var
447 36.4 33.4 +3.0
472 39.0 39.1 -0.1
496 40.1 38.5 +1.6
562 40.4 39.9 +0.5
454 40.1 39.3 +0.8
446 39.6 38.6 +1.0
530 42.2 42.2 0.0

(Sorry about the first tankful, the wife was driving it a lot when the car was new)

 

Mine is within 2 mpg - generally 1.

36 or so in the winter and 39-41 in the summer