About 10 to 20 miles apparently. Shocking : Tesla Model S gets 26.5 mpg I think this estimate is pretty good because it takes data from the EPA/ANL for the national average, and State of CA for a regional average. Anyhoo, long story short, we use natural gas, coal, and electricity, that could otherwise be used to create/send electricity to a homeowner with an EV. Across the US, this ends up being ~3.5+kWh of electricity equivalent (EE) per gallon of gas. In states where petro extraction/refining is more energy intensive, this ends up closer to ~5.5+kWh/gallon. While not exact, it's far less hand-wavy anything else I've seen and matches up really well with the WTW figures ANL uses in their GREET model. The next time someone complains about EVs using electricity, I'll mention that ICEs do too. About 10-20 miles worth depending on the circumstances.