Montana home charging cost for the 2026 Rivian R1S Dual Large Plus (20in)

A 2026 Rivian R1S Dual Large Plus (20in) draws 43.1 kWh per 100 miles per the EPA; at Montana's 13.77¢/kWh residential rate that's $5.94 per 100 miles charged at home, versus $16.02 for a 25.5-mpg gas car covering the same distance. Charging at home is much cheaper than gas here: 62.9% less than gas per mile, here specifically.

What a year of driving costs

At fueleconomy.gov's default of 15,000 annual miles, the 2026 Rivian R1S Dual Large Plus (20in) costs roughly $891 a year to charge at home in Montana, against roughly $2,403 a year for an equivalent gas car. That's a savings of about $1,512 a year.

What one full charge costs

Covering the 2026 Rivian R1S Dual Large Plus (20in)'s EPA-rated 317-mile range takes about 136.7 kWh, which costs about $18.82 at Montana's residential rate — figured from the EPA's own combined range and consumption numbers, not the pack's nameplate capacity.

Where this ranks

This combination ranks 9,127 of 20,400 state/model pairs for cost savings against gas (1 is cheapest). The Rivian R1S Dual Large Plus (20in) alone ranks 327 of 400 models for efficiency; Montana alone ranks 10 of 51 states for electricity price.

Next step: home charger installation

The numbers above assume Level 2 home charging is already in place — the electrical work behind that is a real, separate cost that varies by panel, wiring, and local labor rates, not something this page's per-mile math includes.

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

Where these figures come from

Every figure on this page traces to a named EIA or EPA dataset — see the methodology guide. Curious how Montana's 13.77¢/kWh compares? The guide to charging cost by state ranks every state side by side.