OneTaskBy Tim King · Updated
EV Charging Cost Calculator
Cost, Range Added and Time to Charge
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How the EV Charging Cost Calculator works
This EV charging cost calculator works out what a charge costs your electric car, how much range it adds and how long it takes. Enter the battery size, the start and target charge and your price per kWh, and compare the running cost per 100 km with a petrol car.
How the EV charging cost calculator works
The formula is: cost = battery kWh × (target % − start %) ÷ (1 − charging loss) × price per kWh. Some energy is lost as heat in the charger and battery, typically 10 to 15% on a home wall box and less on DC fast chargers, so you pay for more than the battery stores.
First example. Charging a 60 kWh battery from 20% to 80% puts 36 kWh in. With 10% loss the meter counts 40 kWh, so at $0.30 a kWh the charge costs $12.00 and, at 17 kWh/100 km, adds about 212 km. On a 7 kW wall box it takes about 5 h 43 min.
Second example. At 17 kWh/100 km the EV costs $5.67 per 100 km. A petrol car using 7.5 L/100km at $2.00 a litre costs $15.00, so the EV saves $9.33 every 100 km.
How many kWh does an EV use per 100 km? Most cars use 14 to 20 kWh/100 km, or 3 to 4.5 miles per kWh. Large SUVs and motorway driving in winter can reach 25 kWh/100 km.
The charging time assumes the full charger rate all the way. DC fast chargers slow down sharply above about 80%, so a charge to 100% takes much longer than the page shows.
EV charging cost by electricity price: 60 kWh battery, 17 kWh/100 km, 10% charging loss, compared with a 7 L/100km petrol car at $2.00 per litre
| Price per kWh | Full charge 0–100% | Charge 10–80% | Per 100 km | Per 15,000 km | Saving per 100 km vs petrol |
|---|---|---|---|---|---|
| $0.08 | $5.33 | $3.73 | $1.51 | $227 | $12.49 |
| $0.10 | $6.67 | $4.67 | $1.89 | $284 | $12.11 |
| $0.12 | $8.00 | $5.60 | $2.27 | $341 | $11.73 |
| $0.14 | $9.33 | $6.53 | $2.64 | $396 | $11.36 |
| $0.16 | $10.67 | $7.47 | $3.02 | $453 | $10.98 |
| $0.18 | $12.00 | $8.40 | $3.40 | $510 | $10.60 |
| $0.20 | $13.33 | $9.33 | $3.78 | $567 | $10.22 |
| $0.22 | $14.67 | $10.27 | $4.16 | $624 | $9.84 |
| $0.24 | $16.00 | $11.20 | $4.53 | $680 | $9.47 |
| $0.26 | $17.33 | $12.13 | $4.91 | $737 | $9.09 |
| $0.28 | $18.67 | $13.07 | $5.29 | $794 | $8.71 |
| $0.30 | $20.00 | $14.00 | $5.67 | $851 | $8.33 |
| $0.32 | $21.33 | $14.93 | $6.04 | $906 | $7.96 |
| $0.34 | $22.67 | $15.87 | $6.42 | $963 | $7.58 |
| $0.36 | $24.00 | $16.80 | $6.80 | $1,020 | $7.20 |
| $0.38 | $25.33 | $17.73 | $7.18 | $1,077 | $6.82 |
| $0.40 | $26.67 | $18.67 | $7.56 | $1,134 | $6.44 |
| $0.42 | $28.00 | $19.60 | $7.93 | $1,190 | $6.07 |
| $0.44 | $29.33 | $20.53 | $8.31 | $1,247 | $5.69 |
| $0.46 | $30.67 | $21.47 | $8.69 | $1,304 | $5.31 |
| $0.48 | $32.00 | $22.40 | $9.07 | $1,361 | $4.93 |
| $0.50 | $33.33 | $23.33 | $9.44 | $1,416 | $4.56 |
| $0.52 | $34.67 | $24.27 | $9.82 | $1,473 | $4.18 |
| $0.54 | $36.00 | $25.20 | $10.20 | $1,530 | $3.80 |
| $0.56 | $37.33 | $26.13 | $10.58 | $1,587 | $3.42 |
| $0.58 | $38.67 | $27.07 | $10.96 | $1,644 | $3.04 |
| $0.60 | $40.00 | $28.00 | $11.33 | $1,700 | $2.67 |
FAQ
How much does it cost to charge an electric car?
Multiply the energy you add by your price per kWh, plus about 10% for losses. Adding 50 kWh at $0.25 a kWh costs about $13.90. Public fast chargers often charge two to three times the home rate.
How long does it take to charge an EV?
Divide the energy drawn by the charger power. A 40 kWh top-up takes about 5 hours 40 minutes on a 7 kW wall box, 18 hours on a 2.3 kW socket and around 40 minutes on a 60 kW DC charger.
Why charge only to 80%?
Lithium-ion batteries age faster when they sit full, and DC charging slows a lot above 80%. Many makers suggest 80 or 90% for daily use and 100% only before a long trip. Check your car's manual.
What is the break-even electricity price?
It is the price per kWh at which the EV costs the same per 100 km as the petrol car you entered. Below it the EV is cheaper to run. Above it, as at some expensive fast chargers, the petrol car wins.
What does usable battery capacity mean?
It is the energy the car lets you use, which is a little less than the gross capacity because some is held back to protect the battery. Use the usable figure from the maker's specifications for the best result.
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