EV Charging Cost Calculator

What this EV charging cost calculator does

The calculator turns a battery specification and a tariff into an estimated session cost. Enter how big the battery is in kilowatt-hours, what state of charge you start and end at, what your electricity price is per kWh and what charging efficiency you assume. The result is the amount of money the session adds to your electricity bill, expressed in your selected currency.

It is designed for owners, prospective buyers, fleet planners and anyone comparing electricity costs against petrol or diesel running costs. The same method works for home wallbox charging, public AC charging and DC fast charging — only the price per kWh and the charging efficiency change.

How EV charging cost is calculated

Charging cost is the energy drawn from the wall multiplied by the electricity price. Energy drawn from the wall is the energy that reaches the battery divided by the charging efficiency. Energy that reaches the battery is the battery capacity multiplied by the change in state of charge.

The full formula is: battery kWh × change in state of charge ÷ 100 ÷ charging efficiency × price per kWh. The change in state of charge is the difference between the percentage you finish at and the percentage you started at. The 100 in the formula converts the percentage into a fraction. Charging efficiency is entered as a percentage between roughly 80 and 95 and converted to a fraction internally.

Why charging efficiency matters

Your electricity meter counts every kilowatt-hour the charger pulls from the grid, including the energy lost as heat in cables, the onboard AC-to-DC converter, the battery management system and the thermal conditioning that keeps cells in their preferred temperature range. The battery only stores a fraction of that energy.

A 90 percent efficient session means that for every 10 kWh of energy stored in the battery, the charger drew about 11.1 kWh from the wall. Ignoring losses understates your bill by roughly that ratio. Slow trickle charging from a household socket can be less than 85 percent efficient; a modern wallbox is typically 88 to 92 percent; DC fast charging is often 92 to 95 percent at the meter.

Home charging vs public charging

Home charging is the cheapest option in nearly every country covered on this site. Residential electricity is billed at the household tariff, which can be as low as 0.10 to 0.20 per kWh on overnight EV plans, and is rarely above 0.40 per kWh on standard contracts. Time-of-use tariffs that price overnight hours far below daytime hours make home charging cheaper still.

Public AC chargers at workplaces, supermarkets and on-street locations often sit in the same range as expensive home tariffs. Public DC fast chargers price for speed: rates of 0.50 to 0.80 per kWh are common across Europe and North America, and premium ultra-rapid networks can exceed that. The calculator handles both: enter your home rate to model a typical week, then re-run with a public rate to estimate the marginal cost of a road trip.

AC charging vs DC fast charging

AC charging delivers alternating current to the car. The car's onboard charger converts that AC into DC for the battery. Domestic AC charging is usually limited to 7.4 kW on a single-phase wallbox or 11 kW to 22 kW on three-phase European supplies, with the actual rate capped by whichever is lower between the supply and the onboard charger.

DC fast charging bypasses the onboard charger and delivers DC directly to the battery, which is why it can run at 50 kW, 150 kW or higher. The trade-off is cost: DC chargers are expensive to install and operate, so the price per kWh is normally two to three times the home rate. DC sessions also taper above 80 percent state of charge, which is why charging beyond 80 percent on a road trip rarely makes sense.

Worked example: small EV battery (40 kWh)

A small city EV has a 40 kWh battery, uses 14 kWh per 100 km in mixed driving and charges at home on a 0.22 per kWh tariff at 90 percent efficiency. Charging from 20 percent to 80 percent puts 24 kWh into the battery and draws 26.7 kWh from the wall, costing about 5.86. A full 0 to 100 percent charge from empty draws about 44.4 kWh from the wall and costs 9.78. Cost per 100 km works out to about 3.42.

Worked example: medium EV battery (60 kWh)

A mainstream long-range EV has a 60 kWh battery, uses 17 kWh per 100 km on average and charges at home for 0.28 per kWh at 90 percent efficiency. A 20 to 80 percent home charge puts 36 kWh into the battery, draws 40 kWh from the wall and costs 11.20. A full charge from empty draws 66.7 kWh and costs 18.67. Cost per 100 km works out to about 5.29. The same battery on a 0.65 per kWh DC fast charger from 10 to 80 percent costs about 30.33.

Worked example: large EV battery (90 kWh)

A large electric SUV has a 90 kWh battery, uses 22 kWh per 100 km in motorway driving and charges at home for 0.30 per kWh at 90 percent efficiency. A 20 to 80 percent home charge puts 54 kWh into the battery, draws 60 kWh from the wall and costs 18.00. A full charge costs about 30.00. Cost per 100 km works out to about 7.33. On the road the same SUV charging from 10 to 80 percent on a 0.70 per kWh ultra-rapid charger costs about 49.00 for that single session.

How to estimate cost per mile and cost per 100 km

Once you know the wall energy needed per unit distance and the electricity price, cost per distance is simple. Cost per 100 km equals consumption in kWh per 100 km divided by charging efficiency, multiplied by the electricity price. Cost per mile equals consumption in kWh per mile divided by charging efficiency, multiplied by the price, where consumption in kWh per mile is roughly consumption in kWh per 100 km divided by 62.1.

Use the dedicated cost per 100 km calculator and cost per mile calculator if you would rather enter consumption directly. Both apply the same formula and accept your real tariff and your real efficiency assumption.

Why electricity prices vary by country and tariff

Electricity prices reflect the generation mix, transmission costs, taxes, network fees and retail margins in each market. Countries with abundant hydropower or nuclear generation, such as Norway, France and Sweden, often have lower wholesale rates. Countries that import gas or coal for electricity generation tend to have higher rates, and rates that move with fuel markets.

Within any country, the tariff you actually pay depends on the time of day, the day of the week, the season and whether you are on a regulated or market contract. Time-of-use EV tariffs price overnight hours far below daytime hours, which is why charging schedule matters as much as charger choice. The country pages on this site publish reference residential rates so you can compare like for like, then replace the default with your own number for an accurate estimate.

Common mistakes when estimating EV charging cost

The most common mistake is using the nameplate battery capacity instead of usable capacity. The nameplate figure includes a buffer reserved by the battery management system; the usable capacity is what is available between 0 and 100 percent on the dashboard. Manufacturers publish both, but only usable capacity should be entered into a charging cost calculator.

The second mistake is ignoring charging losses entirely. The third is comparing a public DC fast charge price against a petrol cost per kilometre instead of against a home charge price. The fourth is forgetting subscription fees, idle fees and connection fees on public networks. The fifth is using a summer consumption figure to estimate a winter bill. The calculator cannot eliminate these errors, but it makes the assumptions explicit so they are easy to review.

Who this calculator is useful for

Current EV owners use it to verify a public charger quote against their home rate, decide whether a tariff change is worth it and budget annual charging costs. Prospective buyers use it to test whether a more efficient car with a smaller battery is actually cheaper to run than a larger one. Fleet operators use it to model per-vehicle running costs before committing to electrification. Journalists, teachers and students use it as a transparent reference for how electric driving cost is computed.

Limitations and assumptions

This calculator produces an estimate, not a guaranteed figure. It assumes a fixed electricity price for the whole session, a single charging efficiency value and a battery that accepts charge linearly between the start and end percentages. Real sessions involve variable network pricing, tapering charge curves above 80 percent state of charge, thermal preconditioning losses and cold-weather penalties.

Country reference prices are residential averages drawn from the sources listed on the data sources page, including Eurostat, Ofgem and the U.S. EIA. They are good for like-for-like comparison but should be replaced with your actual contract rate for accurate budgeting. Currency conversions are not applied: each country page uses the local currency reported by the source.

Frequently asked questions