$20.29full charge
The R1S Premium Long Range (120 kWh) costs about $20.29 to charge fully at South Dakota's average home rate of 15.37¢/kWh, including ~10% charging loss (132 kWh from the wall). That is $4.95 per 100 miles.
EIA residential average, South Dakota, 2026-07 (latest in this book). No South Dakota gasoline series, so this uses PADD 2 regular, week of Oct 5, 2026.
At 1,000 miles a month and 30 mpg, home charging costs $49.48 and the gas car costs $136.97. The EV saves $87.48 a month at $4.109/gal. Both miles and mpg are editable on the calculator.
The listed DC fast-charge time to 80% is 30 minutes at up to 220 kW. A full home charge is a different session. This page prices the energy from the wall, not how long a Level 2 charger takes.
This page uses the residential rate. Public fast-charging prices are a separate scenario and are not included.