I wanted to figure out mpg for my driving, but a cost based calculation is more accurate due to different way Clarity can be powered. So we did our first gas fill after 19 days of purchase, unlike many others on this forum, our electric charging is mostly opportunistic due to expensive electricity rates. Here is the calculation Home : 48c per kWH * 45kWH used (approx) = $21.6 Yikes, I knew this before purchase Work : 15c per kWH * 69.34kWH used = $10.4 Gas : $3.8 per gallon * 5.1 gallons filled = $19.38 Total cost = $51.38 = $21.6 (home charging) + $10.4 (work charging) + $29.78 (gas) Total miles driven for first fill up = 550 Cost per mile = $51.38/550 = 9.3c per mile MPG = 40.74 (Reverse the above calculation, $51.38/3.8 per gallon = 13.5 gallons of gas can be purchased. That will give us 550 miles driven/13.5 gallons = 40.74 mpg) If we purely drove in hybrid using gas which claims 42mpg (combined) on label, we'll get $3.8 per gallon /42 miles = 9c per mile. Unlike many others on this forum we are getting less than 40 mpg, probably due to hilly region in San Diego, CA and we go up and down all the time and mostly abrupt stop and go traffic with speeds upto 75 mph on highways, its also been hot so the AC is on most of the time.