Only roughly. Fuel consumption depends on so many things, driving style, weight of the vehicle, road condition, tyre pressure, what electrical devices are running - even whether the windows are up or down. Your computer will be applying your recent consumption rate against what is left in the tank to come up with a figure but I wouldn't rely on it, although most manufacturers ensure that the algorithims used in the calculation will err on the side of caution - so you probably can travel further than it says but not wise to try it.