What do you think of the way I measure MPG?

I'm surprised a 9x7 notebook fits in the glovebox. In the prime it's quite small. Thanks for all the juicy details! My book is more or less the same, though I don't track values that can be derived from others (price per gallon given total gallons and total price). Not much space in a 4"x6" book.

 

The glove box on the 2nd generation is really quite generous. Plenty of room for the 9x7. In addition to the 12 columns there are also additional columns to the left that are not counted as part of the 12. That effectively makes it 14 columns. If you could find a place to keep it in the car you could easily adjust it for your electrical entries.

 

I make an electronic note every time I get gasoline and then put that info into fuelly. I'm also trying to leave my car's ongoing MPG (in the Consumption screen) for as long as possible to give me a decent long-term estimate and check its accuracy. The last time it was reset was in March (by accident) and currently it reads 47.4 MPG as compared to 44.2 overall on Fuelly.

 

I tried electronic notes with previous cars and found I lacked the discipline to do it every time to develop it as habit. This book works since I take the book out before or when I get to the station. I write the date, location, odometer reading, price and MFD mileage before I get out of the car. Then I put it open face on the driver's seat when I go in to pay. That way I can't sit down without being reminded to fill in the gallons and total price from the pump. I calculate the mpg and key into the apps, fuelly and fueleconomy.gov whenever it's convenient. There have been a few times I forgot the book when I first got to the station but then I remembered while the gas was pumping. I just walked around the car and got it before the pump was done.

 

For my last car, I would save the receipts and then put that info in Fuelly, but several times I forgot to bring the receipts inside so I could type in the info, and eventually there were so many receipts that had piled up in my car, I got overwhelmed and just stopped. With my current system, I write the notes on my phone and typically I won't forget that in my car, so it works better.

 

I commend you for being disciplined enough to key things in. I always have the phone on my hip but I would often forget to pull it out and key everything in. I tried collecting receipts but I kept losing them.

 

For me, I just pull out my phone as I get to a pump, type in the mileage and price before shutting off the car. Once I'm done pumping I entered in the gallons used on the pump into the Fuelly app and it updates right then.