According to the U.S. government:
Energy efficient. EVs convert over 77% of the electrical energy from the grid to power at the wheels. Conventional gasoline vehicles only convert about 12%–30% of the energy stored in gasoline to power at the wheels.
Source: All-Electric Vehicles
Of course, one must also include the conversion of the original fuel source into electricity but that depends on the original fuel source: oil, natural gas, coal, nuclear power, hydro, geothermal, solar, wind and so on – and can vary widely.
Regardless, gasoline engines are not very energy efficient in terms of turning the energy in fuel into forward motion, as noted above and also noted here. EVs have a slightly different problem – while they use electricity efficiently, EVs weigh quite a bit more than a similar sized gasoline vehicle.
