EV Charging Cost Calculator
What it costs to charge an electric car at home, per charge and per hundred kilometres.
Charging cost is battery energy divided by charger efficiency, times your rate.
How the ev charging cost calculator works
Charging cost is battery energy divided by charger efficiency, times your rate. The efficiency matters: AC charging loses roughly 10 to 15% in the onboard converter and to battery thermal management, so you pay for more than the battery receives.
The comparison people actually want is cost per hundred kilometres against petrol. An efficient EV uses 15 to 18 kWh per 100 km; at typical home rates that is a small fraction of what the equivalent petrol costs, and the gap widens dramatically if the charging happens on an off-peak or solar-surplus rate.
Public fast charging is a different economic proposition and often several times the home rate.
Formula: cost = kWh added / efficiency × rate
Worked examples
| Inputs | Cost of this charge | Note |
|---|---|---|
| 20% to 80% on a 64 kWh battery | $13.96 | 38.4 kWh added, about 14 |
| On an off-peak rate | $5.24 | less than half |
| A full charge | $23.27 | 64 kWh into the battery |
FAQFrequently asked questions
How much does it cost to charge an electric car at home?
Battery energy added divided by charging efficiency, times your rate. A 20–80% charge on a 64 kWh battery adds 38.4 kWh and draws about 44.
Why do I pay for more than the battery receives?
AC charging loses 10 to 15% in the onboard converter and to thermal management. That energy is metered but never reaches the cells.
Is home charging cheaper than public fast charging?
Substantially — public DC charging is commonly several times the home rate, which is what pays for the hardware and the grid connection.
What is a typical consumption figure?
15 to 18 kWh per 100 km for an efficient car; large SUVs and cold weather push it well above 20.
Should I charge to 100%?
For lithium batteries, routinely charging to 80% and only filling before a long trip is the common manufacturer guidance.
Where these figures come from
- International Energy Agency — Energy Efficiency — appliance consumption and standby power context
- Australian Energy Regulator — the Australian energy market regulator
Last checked: September 2026. Appliance power figures are typical ratings; check the label on your own equipment, which is authoritative for it.