here in the uk my dad has a honda jazz,which is the same as a honda fit in the us,its tank is 9.2 imperial gallons,or 11.1 of your us gallons,in the uk the jazz is availiable with a 1.2,or 1.3 litre engine.my dad has the 1.3 and regularly gets 42 mpg in the town!!hes retired and doesnt drive much,hes done 10,000 miles in 5 years!!!quite often you will get at least half a gallon more in when you brim the tank up to the filler pipe,but youre best just filling up until the pump clicks off.