I’ve heard various claims on how long it takes for an EV to be a better choice than a gas powered car as far as CO2 emissions go. Lots of times it’s some generic time claim, like ‘2 years’. But that doesn’t account for how many miles are driven, or the gas car being used in the calculation. I found this calculator that lets you pick the specific EV, the mpg of the gas car, and your location (different areas of the country fuel their electricity with different mix of fossil fuels, solar, etc.).
I make no claim to its accuracy, but it covers all the important factors for the comparision: