EV & charging
EV vs petrol break-even: how to calculate it
An EV can be cheaper to run and more expensive to buy. A break-even calculation shows how long the running-cost saving would take to recover the price difference, using the numbers you enter.
Quick answer
Annual saving = petrol annual cost − EV annual cost. Break-even years = upfront price difference ÷ annual saving. If the saving is zero or negative, there is no simple break-even.
Key takeaways
- Use the same annual distance for both cars.
- Include charging losses and your real electricity price.
- Break-even is not a total-cost comparison.
The formula
The calculation has two steps. First, compare annual energy costs. Second, divide the price difference by the annual saving. A positive saving means the EV is cheaper to run on the inputs provided.
annual saving = petrol annual cost − EV annual cost break-even years = upfront price difference ÷ annual saving
A worked example
Suppose the petrol car costs 1,800 a year in fuel and the EV costs 700 a year in electricity. The annual saving is 1,100. If the EV costs 5,500 more to buy, the simple break-even is 5,500 ÷ 1,100 = 5 years.
Change the electricity price or annual distance and the answer changes. That is why the inputs matter more than a headline claim.
What it leaves out
The simple break-even excludes depreciation, insurance, maintenance, tyres, road tax, charger installation and resale value. Those can change the answer substantially.
Use the result as a running-cost comparison, not a full financial recommendation.
Questions
How long does it take an EV to break even?
Does break-even include maintenance?
What if electricity is expensive?
Sources
- US EPA — fuel economy and EV range testing — Explains MPGe and the test basis for EV efficiency.
- fueleconomy.gov — understanding the EV label — How MPGe, kWh/100 miles and range appear on US labels.
- US DOE Alternative Fuels Data Center — home charging — Home charging equipment, tariffs and practical considerations.
- US EPA — electric vehicle myths — Common EV efficiency, emissions and charging questions.
- US EIA — electricity data — US electricity prices, generation and sales data.
Try the calculator
Related guides
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Hybrid vs petrol running cost
Compare hybrid and petrol fuel costs using the same annual distance, realistic MPG and your own fuel price.
A note on prices and rules
Page last reviewed: . Formulas are covered by automated tests. Prices are inputs, not live data.