Originally Posted by mamorgan2

I think a major factor that it comes down to is when you stop pumping gas into your tank. Do you "top it off" after the first time the pump clicks off or not? I don't know the "correct" answer, but I would guess that being consistent (either always or never topping it off and using the same gas pump) would give you the most accurate results. As to whether that would help the hand calculations match up to the readout, I don't know.