EV Charging Cost Calculator
Cost of charging an EV per charge, per km and per month, compared with petrol
| Period | Distance (km) | EV | Petrol car | Difference |
|---|---|---|---|---|
| 1 month | 1,200 | ā¹1,488 | ā¹8,000 | ā¹6,512 |
| 1 year | 14,400 | ā¹17,851 | ā¹96,000 | ā¹78,149 |
| 5 years | 72,000 | ā¹89,256 | ā¹4,80,000 | ā¹3,90,744 |
Runs entirely in your browser. Nothing you type or upload is sent to us or stored.
Results are for general guidance. Please check anything important before relying on it. Terms of use
How to Use
- Enter your EV's usable battery size in kWh and the charge level you start from and charge to (for example 20% to 100%).
- Choose home or public fast charger, then enter the price per kWh (unit) from your electricity bill or the charging app, and the charging efficiency.
- Enter the real range you get on a full charge and how many km you drive a day.
- Enter a petrol car's mileage and today's petrol price to compare.
- The cost per charge, cost per km, monthly cost and savings update as you type. Scroll down for the month, year and 5-year comparison.
How much does it cost to charge an electric vehicle?
The cost of charging an EV depends on four things: how much energy goes into the battery, how much is lost while charging, the price you pay per unit (kWh) of electricity, and how far that charge takes you. This calculator works through all four, gives you the cost per charge and per kilometre, and compares it with a petrol car using prices you enter. No fuel or electricity prices are built in: they change by city and by month, so use the numbers from your own bill, charging app and petrol pump.
The formula
Energy you pay for (kWh) = energy into battery Ć· charging efficiency
Cost per charge = energy you pay for Ć rate per kWh
Range from the charge = full-charge range Ć (to % ā from %)
EV cost per km = cost per charge Ć· range from the charge
Petrol cost per km = petrol price Ć· mileage (km/l)
Worked example
A car with a 30 kWh usable battery is charged at home from 20% to 100%. That puts 30 Ć 0.8 = 24 kWh into the battery. At 88% charging efficiency the meter records 24 Ć· 0.88 = 27.3 units. At ā¹8 a unit the charge costs ā¹218. If the car really does 220 km on a full charge, 80% gives 176 km, so the cost is ā¹218 Ć· 176 = ā¹1.24 per km. A petrol car doing 15 km/l with petrol at ā¹100 a litre costs ā¹6.67 per km. At 40 km a day (1,200 km a month) that is about ā¹1,490 a month for the EV against ā¹8,000 for petrol.
Typical values to start with
| Input | Where to find it |
|---|---|
| Usable battery (kWh) | The car's spec sheet. Electric scooters are usually a few kWh; cars range from about 25 kWh to over 80 kWh. |
| Home rate (ā¹/kWh) | Your electricity bill: the energy charge for your slab plus fixed charges and electricity duty, divided by units. Some DISCOMs offer a separate EV or time-of-day tariff. |
| Public charger rate (ā¹/kWh) | The charging app shows it per kWh. Check whether GST, a session fee or idle fees are extra. |
| Charging efficiency | Home AC charging typically loses 10ā15% (85ā90% efficiency). Public DC chargers bill the energy at their meter, so a higher figure suits them. |
| Real range | Your trip computer, not the certified figure, which is measured under test conditions. |
Why charging from 20% to 80% is common
Lithium-ion batteries charge fastest in the middle of their range and slow down sharply near full, so on a DC fast charger stopping at around 80% saves time. Many manufacturers also suggest not keeping the battery at 100% for long periods for daily use. For cost per km it makes no difference: you pay for the energy you add, and the range scales with it. Use the "charge from" and "charge to" fields to model your own habit.
What this doesn't include
- The price of the vehicle, insurance, maintenance or battery replacement. For the full picture over several years, use the EV vs petrol cost calculator.
- The cost of installing a home charger, or a separate meter connection.
- Range loss from air-conditioning, highway speeds and hot weather. Using your real range already captures most of it.
Tip: at home, charging during off-peak hours can be cheaper where your DISCOM offers a time-of-day tariff. Check your state electricity regulator's current tariff order.