Well, I had my wife and my 19 and 15 year old kids in the car, a large cooler, 3 suitcases (all in the car) plus an EZ up, 3 folding camping chairs, a foldable wagon and two baseball bags in the roof box, AC on (it's 115 in AZ today) and I got 23.9 mpg, all freeway going 75 ish. Not bad at all.