kWh per 100 Miles Cost Calculator: EV Cost per Mile, MPGe and Gas Comparison
Turn an EV’s energy use (kWh/100 mi, kWh/100 km, Wh/mi or mi/kWh) and your electricity rate into the cost per 100 miles, per mile and for any distance, with MPGe, unit conversions, charging losses and a side-by-side cost against a gas car.
How it works
Cost per 100 mi = kWh/100 mi × rate per kWh · Cost per mile = cost per 100 mi ÷ 100 · kWh/100 mi = 100 ÷ mi/kWh = Wh/mi ÷ 10 = kWh/100 km × 1.609 · MPGe = 3,370.5 ÷ kWh/100 mi · With charging losses: kWh from the wall = kWh from the battery ÷ (1 − loss)
An electric car’s running cost per mile is the energy it uses per mile times what you pay for a kilowatt-hour. Multiply the kWh per 100 miles by your rate for the cost per 100 miles, and divide by 100 for the cost per mile. Efficiency can be entered as kWh/100 mi, kWh/100 km or Wh/mi, or as miles (or km) per kWh, the way many dashboards show it. The EPA’s kWh/100 mi figure on the window sticker is measured at the wall, so it already includes charging losses. A car’s own display usually counts energy leaving the battery, which is lower; under More options you can add a percentage for the losses in the charger and cable. MPGe restates efficiency on the familiar mpg scale using the EPA equivalence of 33.7 kWh (33.705 kWh) per gallon of gasoline; it compares energy, not money. The gas-car comparison prices the same distance at your gas price and mpg, and the break-even rate is the electricity price at which the EV and the gas car cost the same per mile. The table shows how the cost changes between cheap off-peak home charging and expensive public fast charging.
Worked example
An EV rated at 30 kWh per 100 miles, charged at home at $0.18 per kWh, costs 30 × 0.18 = $5.40 per 100 miles, or $0.054 a mile. Driving 1,000 miles uses 300 kWh and costs $54.00. Its MPGe is 3,370.5 ÷ 30 = 112. A 30 mpg gas car at $4.29 a gallon costs $14.30 per 100 miles, so the EV saves $89.00 over the 1,000 miles, and it would only cost as much as the gas car at about $0.477 per kWh.
Sources: EPA: Fuel economy and EV range testing (33.7 kWh per gallon; MPGe includes charging losses) · Inch Calculator: kWh/100 mi to MPGe (3,370.5 constant) · Inch Calculator: Electric vehicle efficiency converter · EIA Electric Power Monthly: average residential price (Aug 2026) · AAA national average gas price (Oct 2026)
Frequently asked questions
What is a good kWh per 100 miles?
Efficient small EVs and sedans use roughly 25 to 30 kWh per 100 miles; large SUVs and pickups often use 40 to 50 or more. Lower is better. Cold weather, high speed and heavy loads raise the figure.
How do I convert mi/kWh to kWh/100 miles?
Divide 100 by the miles per kWh. For example, 4 mi/kWh is 100 ÷ 4 = 25 kWh/100 mi, which is about 15.5 kWh/100 km and 134.8 MPGe. Pick Distance per kWh above to enter it directly.
What is MPGe?
Miles per gallon of gasoline-equivalent restates electric efficiency on the gas mpg scale. The EPA treats 33.7 kWh of electricity as energy-equivalent to one gallon of gasoline, so an EV using 33.7 kWh per 100 miles gets 100 MPGe, and MPGe = 3,370.5 ÷ kWh/100 mi.
Does kWh/100 miles include charging losses?
The EPA figure on the window sticker does: it is measured at the wall with Level 2 charging. The number on the car’s screen usually is not, so add the charging losses under More options if that is the figure you enter.
Is charging an EV cheaper than buying gas?
At typical US home electricity rates, usually yes: 30 kWh/100 mi at 18 cents is $5.40 per 100 miles, versus about $14.30 for a 30 mpg car at $4.29 a gallon. Public DC fast charging, which often costs several times the home rate, narrows or removes the gap; the break-even rate shows where.
Related calculators
Educational estimate: real energy use and rates vary with the vehicle, weather, driving and your utility’s tariff.