Google search for "convert km per liter to miles per us gallon" provide a calculator and conversion factor of 2.35214583, ie: km per liters times 2.35214583 equals mpg (US). My favourite is for converting liters per 100 km to mpg US. Divide either value into 235.2. It'll flip/flop between the two systems. I worked it out once, currently forget how, just cling to that value, lol.
funny how css28 got the same as me, but i did it again and it's 30. not bad if it's really bad stop and go.