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Electric Car Savings Calculator
Compare the cost of running an electric car against a petrol car. Enter your annual mileage, fuel and electricity prices, and the two purchase prices, and see your yearly fuel costs side by side, your annual and 5-year savings, the year the electric car pays for itself, and the CO2 you keep out of the air.
Most electric cars manage 3 to 4 miles per kWh in mixed driving. Your electricity price is on your bill, per kWh.
Cumulative savings over time
The blue line starts below zero by the extra purchase price, then climbs by your annual fuel saving. Where it crosses zero is the break-even year.
Petrol vs electric
Same miles, different cost per mile.
How it works
An electric car and a petrol car do the same job, but they buy energy in different units at very different prices: petrol by the gallon, electricity by the kilowatt-hour (kWh). This calculator turns both into a cost per year, so you can compare them directly, and works out whether the fuel savings cover the electric car's usually higher purchase price.
Petrol cost per year comes from three numbers: how far you drive, how thirsty the car is, and the price of petrol. Divide annual miles by miles per gallon to get the gallons burned in a year, then multiply by the price per gallon. At 12,000 miles a year and 28 miles per gallon, the car burns about 429 gallons, and at $3.50 a gallon that is $1,500 a year.
Electric cost per year works the same way. Divide annual miles by the car's efficiency in miles per kWh to get the kilowatt-hours used in a year, then multiply by the electricity price per kWh. At 12,000 miles a year and 3.5 miles per kWh you use about 3,429 kWh, and at $0.16 per kWh that is about $549 a year. Cost per mile works the same way: petrol is $3.50 divided by 28 mpg, about 12.5 cents a mile, while electricity is $0.16 divided by 3.5, about 4.6 cents a mile.
Annual saving is simply the petrol cost minus the electric cost. Multiply it by the years of ownership for the total saving over that period. In the worked example below, $951.43 a year over 5 years is $4,757.14. Note that this is a fuel-only saving: it does not include servicing, insurance, tyres or tax.
The break-even year answers the question most buyers actually ask: how long before the fuel savings repay the extra money the electric car cost to buy? Divide the purchase-price difference by the annual saving. If the electric car costs $5,000 more and you save $951.43 a year, break-even is 5.26 years, or about 5.3 years. If the annual saving is zero or negative, the electric car never breaks even on fuel alone, and the calculator says so plainly.
CO2 saved is the tailpipe figure. A petrol car emits about 404 grams of CO2 per mile from its exhaust — a figure you can change in the calculator. Multiply it by your annual miles: 12,000 miles times 404 grams is 4,848 kilograms per year. An electric car has no exhaust, so the whole tailpipe amount is saved. Charging electricity has its own emissions, so the total saving is smaller.
Reading the chart. The chart plots your net position year by year, starting below zero by the extra purchase price and climbing by one year's fuel saving each year. The year it crosses zero is your break-even year, and after that every year adds pure saving. A steeper line means a faster payback, which is what high-mileage drivers see.
Worked example
Take a driver covering 12,000 miles a year. The petrol car does 28 miles per gallon, petrol costs $3.50 a gallon, the electric car does 3.5 miles per kWh, and electricity costs $0.16 per kWh. The electric car costs $35,000, the petrol car $30,000, and the driver plans to keep the car for 5 years.
Step 1: Petrol cost. 12,000 miles ÷ 28 mpg = 428.57 gallons a year. 428.57 × $3.50 = $1,500.00 per year.
Step 2: Electric cost. 12,000 miles ÷ 3.5 mi/kWh = 3,428.57 kWh a year. 3,428.57 × $0.16 = $548.57 per year.
Step 3: Annual saving. $1,500.00 − $548.57 = $951.43 per year.
Step 4: Five-year saving. $951.43 × 5 = $4,757.14.
Step 5: Break-even. $5,000 ÷ $951.43 = 5.26 years, or about 5.3 years.
Step 6: CO2 saved. 12,000 miles × 404 g = 4,848 kg (4.85 tonnes) per year.
Try it yourself: enter 12,000 miles, 28 mpg, $3.50 a gallon, 3.5 miles per kWh, $0.16 per kWh, purchase prices of $35,000 and $30,000, and 5 years. The tool gives exactly the same answers — $1,500.00 a year for petrol, $548.57 for the electric car, $951.43 saved a year, and $4,757.14 over 5 years.
FAQ
How much can I save by switching to an electric car?
It depends on how far you drive and on your petrol and electricity prices. A driver covering 12,000 miles a year in a 28 mpg petrol car at $3.50 a gallon spends $1,500 a year on fuel, while an electric car doing 3.5 miles per kWh at $0.16 per kWh costs about $549 a year to charge — a saving of about $951 a year. High-mileage drivers save more, because every extra mile widens the gap between cheap electricity and petrol.
When does an electric car pay for itself?
Divide the extra purchase price by your annual fuel saving. If the electric car costs $5,000 more and you save $951 a year, the break-even point is about 5.3 years, after which the savings are pure gain. If it costs the same or less to buy, it pays for itself immediately. Servicing can shorten the break-even time, because electric cars have fewer moving parts.
How do I work out my electric car's cost per mile?
Divide your electricity price by your car's efficiency. At $0.16 per kWh and 3.5 miles per kWh, that is $0.16 divided by 3.5, about $0.046 per mile — under 5 cents a mile. For a petrol car, divide the petrol price by the miles per gallon: $3.50 divided by 28 mpg is $0.125 per mile. The electric car costs roughly a third as much per mile here.
Does the calculator include charging at home?
Yes, in the electricity price you enter. If you mostly charge at home, enter your home rate per kWh. If you use public fast chargers often, enter a blended rate — public charging usually costs more per kWh than home charging.
How much CO2 does an electric car save?
A petrol car emits about 404 grams of CO2 per mile from its exhaust, so driving 12,000 miles a year produces about 4,848 kilograms of CO2. An electric car has no exhaust, so the tailpipe saving is the full 4,848 kilograms a year. The real total saving is smaller once charging electricity is counted, but the tailpipe figure is a useful starting point — you can change the 404 grams per mile in the calculator.