EV Charging Cost Calculator

How to use the ev charging cost calculator

Enter the battery size, the state-of-charge window you’re charging across (from one percentage to another), your electricity rate, and — under Advanced — the charging efficiency, and you get the cost of that charge plus the cost of a full 0–100%. The rate varies by state: the US residential average is about 17.5¢/kWh as of 2026, so use the figure from your own bill.

Home versus public is the big cost story. Charging at home on a residential rate is the cheap case this tool models; public Level 2 and especially DC fast charging cost two to four times as much per kWh, and some bill by the minute. The arithmetic is the same — energy times rate — so to price a public session, just enter that station’s rate instead of your home rate.

The 20–80% default reflects how EVs are actually used. Most charging happens in the middle of the pack, not 0–100%: topping to 100% is slower and harder on the battery, and running to empty is impractical and stressful for the cells. Widen the window only when you genuinely need the extra range for a long trip; for daily driving, 20–80% is the normal cycle.

Charging losses are real and worth including. Some grid energy is lost to heat and AC-to-DC conversion before it reaches the battery — typically 10–15% on Level 2 home charging. The Advanced efficiency setting (default 90%) means you draw more from the grid than lands in the pack, and you pay for that difference. DC fast charging is more efficient at the car but is priced higher per kWh, which usually outweighs the efficiency gain.

To compare against gasoline, turn the charge cost into dollars per mile (charge cost ÷ miles added) — at home it’s usually a fraction of gas. Pair this with the fuel-cost calculator to put a drive head to head: a 75 kWh battery charged 20–80% adds a couple hundred miles for under $9 at home, where the same miles in a gas car cost far more.

The formula

Energy into the battery is the capacity times the charge window; grid energy is higher because of charging losses; cost is grid energy times your rate:

energy to battery = battery kWh × (to% − from%)
grid energy = energy to battery ÷ efficiency
cost = grid energy × rate

Worked example with the defaults — a 75 kWh battery from 20% to 80% at $0.175/kWh and 90% efficiency: energy to battery = 75 × 0.60 = 45 kWh; grid energy = 45 ÷ 0.90 = 50 kWh; cost = 50 × $0.175 = $8.75. A full 0–100% equivalent is about $14.58.

The losses matter: at 90% efficiency you pull 50 kWh from the grid to put 45 kWh in the pack. Public DC fast charging changes the price per kWh far more than it changes this math.

Frequently asked questions