What it costs to charge a 2026 Rivian R1S Dual Standard (20in) in Montana

A 2026 Rivian R1S Dual Standard (20in) draws 42.9 kWh per 100 miles per the EPA; at Montana's 13.77¢/kWh residential rate that's $5.9 per 100 miles charged at home, versus $16.02 for a 25.5-mpg gas car covering the same distance. That works out to 63.2% cheaper per mile than gasoline in Montana — charging at home is much cheaper than gas here.

What a year of driving costs

Home charging this 2026 Rivian R1S Dual Standard (20in) in Montana runs about $885 over fueleconomy.gov's default 15,000 annual miles, versus about $2,403 for the gasoline equivalent. Call it about $1,517 saved annually, at this mileage.

Cost of a full charge

$15.23 — that's what Montana's 13.77¢/kWh rate puts on the 110.6 kWh a 2026 Rivian R1S Dual Standard (20in) needs for its full 258-mile EPA range.

2026 Rivian R1S Dual Standard (20in) in Montana, ranked

Among all 20,400 state-and-model combinations this site tracks, charging a 2026 Rivian R1S Dual Standard (20in) in Montana ranks 8,910 for cost savings versus gas — 1 being the best deal nationally. Separately, the Rivian R1S Dual Standard (20in) ranks 312 of 400 EV models for raw efficiency, and Montana ranks 10 of 51 for cheapest residential electricity.

Next step: home charger installation

Everything above is the per-mile and per-year cost once a home charger exists — getting one installed is a separate electrical job whose price depends on your panel and wiring, not the state average used here.

Ask a licensed Montana electrician to quote the install before this math becomes a real decision.

More on how this number was built

The methodology guide names the exact EIA and EPA tables behind this page's numbers. Curious how Montana's 13.77¢/kWh compares? The guide to charging cost by state ranks every state side by side.