EV Home Charging Cost Calculator
Use this EV home charging cost calculator to find out what it really costs to charge your electric car at home. Enter the energy you add to the battery, your electricity price per kWh, and the charging efficiency, and the calculator returns the total cost — including the small amount of energy lost as heat during charging.
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Calculate your home charging cost
Enter values above and press Calculate to see your result.
Formula used
Some energy is lost as heat in the charger and battery, so you draw a little more from the grid than reaches the battery:
Energy from grid = Energy into battery ÷ efficiencyCost = Energy from grid × price per kWh
With the percentage method, energy into the battery is battery size × (end% − start%). Charging overnight on an off-peak tariff dramatically lowers the price per kWh.
Worked examples
Top-up. 40 kWh at $0.30/kWh and 90% efficiency ≈ $13.33.
20→80% on a 60 kWh battery. That's 36 kWh into the battery, ~40 kWh from the grid, about $12 at $0.30.
Off-peak. The same charge at a $0.10 night rate costs only about $4.40.
How to use this calculator
- Choose whether you know the kWh added or want to use battery size and start/end %.
- Enter the energy (or battery size and percentages).
- Enter your electricity price per kWh — use your off-peak rate if you charge overnight.
- Adjust charging efficiency if you know it (90% is typical).
- Press Calculate for the total cost and grid energy used.
Typical home charging costs (per full 60 kWh)
| Electricity price | Energy from grid | Approx. cost |
|---|---|---|
| $0.10 / kWh (off-peak) | ~67 kWh | ~$6.70 |
| $0.20 / kWh | ~67 kWh | ~$13.30 |
| $0.30 / kWh | ~67 kWh | ~$20.00 |
| $0.40 / kWh | ~67 kWh | ~$26.70 |
Assumes ~90% charging efficiency. Off-peak tariffs are the biggest lever on cost.
Who should use this calculator
EV owners and prospective buyers working out running costs, anyone comparing home charging to public charging or to petrol, and those deciding whether an off-peak electricity tariff is worth switching to.
Why charging efficiency matters
Charging isn't perfectly efficient — some energy becomes heat in the onboard charger and battery. At ~90% efficiency, every 10 kWh that reaches the battery costs you about 11 kWh from the meter. The slower the charge and the colder the weather, the larger these losses tend to be.
Cutting your charging cost
- Charge off-peak. Night-rate tariffs can be a third of the day rate.
- Avoid frequent 100% charges unless needed; 20–80% is gentler and usually enough.
- Precondition while plugged in so cabin heating doesn't draw from the battery.
Limitations of this calculator
This estimates electricity cost only. It doesn't include standing charges, the cost of installing a home charger, battery degradation, or seasonal efficiency changes. Real consumption per mile/km varies with driving style, speed and temperature.
Frequently asked questions
How much does it cost to charge an EV at home?
Multiply the energy added by your price per kWh, divided by charging efficiency. A 40 kWh charge at $0.30/kWh and 90% efficiency is about $13.30.
Is home charging cheaper than public charging?
Almost always, especially on an off-peak tariff. Public fast charging often costs two to four times the home rate per kWh.
What charging efficiency should I use?
Home AC charging is typically 85–92%. Use 90% as a reasonable default; slower charging and cold weather reduce it.
How do I work out cost per mile?
Divide the charge cost by the miles (or km) it adds, which depends on your car's consumption. A typical EV uses 3–4 miles per kWh.
Should I charge to 100%?
For daily use, 80% is gentler on the battery and usually enough. Charge to 100% before long trips when you need the range.