The fleet average real-world fuel efficiency for light petrol vehicles in my country, based on government data, is 9.2 litres/100km. (I'm guessing it's significantly worse than this in the USA where the average vehicle is larger and there is less focus on fuel efficiency)

At 8.9 kWh per litre, that means gasoline takes 81.88 kWh to get you 100 km. A typical EV, on the other hand, will use about 18 kWh to go 100 km (at 5.5 km per kWh). That makes the EV around 4.5 times more efficient.

As for carbon emissions, burning 1 litre of gasoline creates 2.3kg of CO2. At 9.2 litres per 100 km, that works out around 210g per km.

Grid carbon intensity varies greatly by country and region. In France at only 42g/kWh, an EV's energy would emit less than 10g per km, even after accounting for grid and charging inefficiencies! But even in coal-dependent Germany at 354g CO2/kWh (2023), an EV would be well under 100g per km, still better than an average petrol car.

(Also, remember that auto industry emissions/efficiency numbers are based on testing protocols which produce far lower figures than the real world. And do not account for upstream emissions in the fossil fuel supply chain - there is an awful lot of upstream carbon emitted to produce 1 litre of gasoline!)

I agree we should look at the whole picture but that would mean to look at how much CO2 is rejected to produce an EV compare to a Petrol car and how much to recycle it.