DSCN0449 Every time I filled up the 2007 Prius (and it was a fill-up every time; I’m not one of those people who put a few dollars in here and there), I wrote down the mileage on the receipt and kept the receipt in the glove box. At first it was basically for legal reasons. As I mentioned before, California has this craziness where if you buy from a California dealership and live outside the state, you 1) cannot bring the car back into the state for 90 days, and 2) must prove that the car was operated primarily outside of the state for the first 6 months, if questioned. Traditionally this is done with gas receipts. After the first 6 months, I just continued out of habit.

Today I dumped all the info to a spreadsheet, and here are the results:

  • 49 fill-ups, first unknown, second on 2007-06-14, last on 2008-10-13 (I noted a base mileage of 135 on the first fill-up, but didn’t record the date.)

  • 20,026 miles driven, 19,667 miles counted as part of this data (first fill-up was at 135, last fill-up was at 19,802)

  • Average 410 miles, 9.266 gallons between fill-ups

  • 444.749 gallons consumed

  • Gas prices: minimum $2.759, maximum $4.299, average $3.399

  • Gas prices changed an average of 12.6 cents between fill-ups

  • Average fill-up: $31.58

  • Total spent on gas: $1515.89

  • Lifetime fuel economy: 44.22 MPG

Gas mileage was a bit lower than I expected, though by looking at the trends on the spreadsheet, it looks like it was mainly when I moved from the University (25 miles round-trip to work) to the Southwest (10 miles round-trip to work). Shorter trips lower fuel economy no matter what kind of car you have, but that is offset by the fact that I’m simply driving fewer miles per day.