How it works
The calculator compares what you spend each year to drive the same distance in a petrol (gasoline) car and an electric car: fuel against electricity, plus servicing and repairs. Electric cars have no oil changes, fewer moving parts and brakes that last longer thanks to regenerative braking, so maintenance is usually lower.
Electricity cost depends heavily on where you charge. Home charging, especially on an overnight EV rate, is cheap; relying on public rapid chargers can cost as much per mile as petrol. Set the share you expect to charge in public.
If the electric car costs more to buy, dividing that extra by the yearly saving gives the number of years until it pays for itself. Insurance, depreciation and finance differ too much between models to estimate here.
The formula
fuel per mile = price per gallon ÷ mpg
(UK: price per litre × 4.546 ÷ mpg; L/100 km: L ÷ 100 × price per litre)
electricity per mile = kWh per mile ÷ 0.9 × blended home/public price per kWh
yearly cost = distance × (energy per mile + maintenance per mile)
break-even (years) = extra purchase price ÷ (gas yearly cost − EV yearly cost)
Worked example
13,200 miles a year. A 30 mpg car at $3.91 a gallon against a Tesla Model 3 (0.25 kWh a mile) charged 90% at home at 18.2¢ and 10% at public chargers at 48¢. The EV costs $5,000 more.
| Step | Working | Result |
|---|---|---|
| Gas per mile | $3.91 ÷ 30 | 13.0¢ |
| Electricity per mile | 0.25 ÷ 0.9 × $0.2118 | 5.9¢ |
| Gas car a year | 13,200 × (13.0¢ + 10.1¢) | $3,054 |
| EV a year | 13,200 × (5.9¢ + 6.1¢) | $1,582 |
| Saving a year | $1,472 | |
| Pays back $5,000 in | 5,000 ÷ 1,472 | 3.4 years |
In the UK, 7,200 miles a year in a 45 mpg petrol car at 174p a litre costs about £1,266 in fuel; an EV charged mostly on an 8p overnight tariff costs about £252 in electricity.
Frequently asked questions
Is an electric car cheaper to run than a gas car?
Usually, if you can charge at home. At US average prices an efficient EV costs about 5.9¢ a mile in electricity against about 13.0¢ for a 30 mpg car, and maintenance is roughly 40% lower. Drivers who rely on rapid public chargers save much less.
How much does an EV save per year?
About $1,470 a year in our US example (13,200 miles), including maintenance. The saving grows with distance and with the gap between fuel and electricity prices.
How long does it take for an EV to pay for itself?
Divide the extra purchase price by the yearly saving. A $5,000 premium pays back in about 3.4 years in our US example. Note the US federal EV tax credit ended for vehicles acquired after September 30, 2025, so check state incentives.
Are EVs cheaper to maintain?
Yes, on average. Argonne National Laboratory estimated about 6.1¢ a mile for battery electric cars against 10.1¢ for gasoline cars, mainly because EVs need no oil changes and their brakes wear more slowly. Tyres can wear faster because EVs are heavier.
What about the cost of charging in the UK?
On an EV tariff around 8p per kWh, an efficient EV costs about 2.2p a mile; at the standard price cap rate of 26.32p it is about 7.3p, and at public chargers far more. A 45 mpg petrol car costs about 17.6p a mile in fuel. See what it costs to charge a Tesla at home for every model.
Sources
- Fuel: EIA forecast 2026 average for regular gasoline (October 2026 STEO); September 2026 averaged $4.35; UK average unleaded, about 174p a litre in mid-October 2026; Canadian average regular, about $1.78 to $1.84 a litre in October 2026 (CAA, NRCan); varies by province; Australian average unleaded, about 242¢ a litre, week ending 18 October 2026 (AIP).
- Electricity: US average residential price, EIA 2026 forecast (checked Oct 2026); Ofgem price cap unit rate, 1 Oct – 31 Dec 2026, Direct Debit (VAT on electricity is 0% until 31 Mar 2027).
- Maintenance: Argonne National Laboratory, Comprehensive Total Cost of Ownership Quantification for Vehicles with Different Size Classes and Powertrains (2021).
- US Department of Energy, vehicle cost calculator.
Estimates are for planning only and are not financial advice. Get written quotes before you buy.