Calculators · EV and electrical

EV charging time and cost calculator

How long an electric car takes to charge depends on how much energy it needs, the charger’s power and the losses along the way. What it costs depends on the electricity price and those same losses. These calculators estimate charging time and cost for a session, and compare the cost per 100 km of an electric car with a petrol or diesel one.

Charging time

Estimates the time to charge from one state of charge to another at a given charger power. Losses of about 10% on AC charging are included. Fast DC charging slows sharply above about 80%, which this simple model does not include, so charge to 80% for the most accurate estimate.

Results
Energy added to battery—kWhEnergy stored in the battery.
Energy drawn from the grid—kWhWhat the meter records, including losses.
Charging time—hoursGrid energy divided by charging power.

Formula
added = capacity × (target − start) / 100
grid = added / efficiency
time = grid / power

Charging cost

Calculates what a charging session costs and the resulting cost per 100 km, allowing for charging losses. Enter your home tariff or the public charger’s price per kWh, in any currency.

Results
Cost of this charge—currencyGrid energy multiplied by price.
Cost per 100 km—currencyIncludes charging losses.

Formula
cost = added energy / efficiency × price
cost per 100 km = consumption / efficiency × price

Electric versus petrol or diesel running cost

Compares energy cost per 100 km and per year for an electric car and a combustion car. It covers energy only — servicing, tyres and insurance also differ between the two.

Results
Electric cost per 100 km—currencyIncluding charging losses.
Petrol/diesel cost per 100 km—currencyFuel cost over 100 km.
Saving per year—currencyNegative means the electric car costs more.

Formula
EV = consumption / efficiency × price
fuel car = l/100 km × fuel price
saving = (fuel car − EV) × distance / 100

Worked example: charging at home

  1. Charging a 75 kWh battery from 20% to 80% adds 45 kWh.
  2. With 90% efficiency the meter records 50 kWh; an 11 kW wallbox takes about 4.5 hours.
  3. At 0.15 per kWh the charge costs 7.50, or 2.83 per 100 km.
  4. A petrol car at 7 l/100 km and 1.50 per litre costs 10.50 per 100 km — about 1,150 more a year over 15,000 km.

Charging time for 45 kWh (20–80% of a 75 kWh battery; 90% AC, 94% DC efficiency)

ChargerPowerApproximate time
Household socket2.3 kWabout 22 hours
Single-phase wallbox7.4 kWabout 6.8 hours
Three-phase wallbox11 kWabout 4.5 hours
DC fast charger50 kWabout 57 minutes
DC ultra-fast charger150 kWabout 19 minutes (if the car accepts it)

Related

EV range, energy consumption and battery health calculatorBattery capacity, runtime and charging time calculatorFuel savings and break-even calculatorRunning costs by class

About these results

Results are theoretical estimates from standard engineering formulas. Real-world figures depend on conditions these formulas do not capture. Always follow the manufacturer's specifications for maintenance, loading and safety decisions.

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