EV Charging Cost Calculator
Work out what one charging session costs, with the conversion loss counted on the side of the meter that actually bills you for it.
The formula, every assumption, and the official sources behind this tool are published on this page.
Results
Session cost: $8.00
Energy you pay for: 44.44 kWh
Lost in conversion: 4.44 kWh
Effective cost per kWh into the battery: $0.20
Same energy, same price per kWh — what the metering loss alone costs
- Home, 120 V outlet (Level 1) — 85% reaches the battery: $8.47 (47.06 kWh billed)
- Home, 240 V charger (Level 2) — 90% reaches the battery: $8.00 (44.44 kWh billed)
- Public DC fast charger — billed on energy delivered: $7.20 (40 kWh billed)
This list holds your price fixed so the only thing changing is metering loss, which is why public DC looks cheapest: it is billed on energy delivered, with no upstream loss on your side of the meter. It is not a comparison of where charging is cheaper. DC networks set their own per-kWh price, usually well above a residential rate, so put that network's posted price in the field above to price a real public session.
How it works
Cost is the energy you are billed for times your rate. The only subtlety is which side of the loss your meter is on, and that depends on where you plugged in.
billed_kwh = kwh_added / metered_efficiency
metered_efficiency = 0.85 (Level 1) | 0.90 (Level 2) | 1.00 (public DC)
cost = billed_kwh × rate
kwh_added- Energy that ended up in the battery, in kWh.
charge_location- l1 and l2 are home charging; dcfc is a public DC fast charger.
metered_efficiency- Share of billed energy that reaches the battery: 0.85 on Level 1, 0.90 on Level 2, 1.00 on public DC. Not a free-form input — pick the location.
rate- Price per kilowatt-hour you are charged.
billed_kwh- kwh_added ÷ metered_efficiency — what the meter counts.
cost- billed_kwh × rate.
Assumptions
- The 40 kWh default is an illustrative session (roughly 20%→80% on a 65 kWh usable pack), not a measurement. Replace it with your own.
- There is no car model dropdown on purpose. Tesla does not publish usable pack energy and EPA's fueleconomy.gov record returns no battery figure for the Tesla, Ford, and Chevrolet EVs we checked, so a model list would mean guessing the number that drives the whole result. Read the kWh added off the car or the charger.
- Home factors are rounded from a Vermont field study of 115 real sessions: 83.8% on Level 1 and 89.4% on Level 2. Your own equipment, cable run, and battery conditioning will move it a few points.
- Public DC uses 1.00 because NIST Handbook 44 §3.40 requires retail chargers to meter and bill in kilowatt-hours delivered — the off-board conversion loss is on the operator's side of the meter. That is a billing fact, not a claim that DC fast charging is lossless.
- Do not start from an EPA window-sticker number here. EPA measures kWh/100 miles at the wall, so the charging loss is already inside it; dividing again by 0.90 overstates the cost by about 10%.
- One price field drives every figure on the page, including the other-location list, so that list compares metering loss at a fixed price and nothing else. Read it as an efficiency comparison, not a cost comparison between places to charge: real public DC pricing is set by the network, varies by site and time of day, and is usually a multiple of a residential rate. No public price is assumed here because there is no national figure worth quoting — enter the one you are actually being charged.
- Cold-weather preconditioning and battery cooling both show up on your meter and are not modelled. A freezing Level 1 session can fall well below 85%.
FAQ
How much does it cost to charge an EV at home?
Adding 40 kWh to the battery on a Level 2 home charger pulls about 44.4 kWh through the meter. At the EIA U.S. residential average of $0.18/kWh that is $8.00 — an effective $0.20 for every kWh that actually reached the battery.
Why is charging at a public DC charger priced differently?
Two reasons. The network sets its own per-kWh price, usually well above a residential rate, and it bills the energy its dispenser delivered to your car, so you are not paying for its conversion loss. Stations that bill per minute are a different calculation entirely — this tool prices energy, not time.
Is Level 1 charging cheaper than Level 2?
No, it costs more for the same energy. Level 1 runs at roughly 85% versus 90% on Level 2, so putting 40 kWh into the battery costs $8.47 instead of $8.00 at $0.18/kWh. Level 1 is slower and slightly more wasteful; it is not a saving.
Sources
- U.S. DOE Alternative Fuels Data Center — Electric Vehicle Charging Stations (Level 1 / Level 2 / DC fast power ratings; captured 2026-09)
- Sears et al., "A comparison of electric vehicle Level 1 and Level 2 charging efficiency" (IEEE, 2014) — 115 logged sessions: Level 1 83.8%, Level 2 89.4%
- NIST Handbook 44 §3.40 Electric Vehicle Fueling Systems — retail EVSE must indicate and bill energy delivered, in kilowatt-hours
- U.S. EPA — Fuel Economy and EV Range Testing: MPGe and kWh/100 mi include charging losses because they are measured at the wall outlet
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