How Many Miles to Break Even on an EV: Formula, Tables and What Is Left Out

The question behind how many miles to break even on an ev is really two smaller questions: what does each car use per mile, and what does that energy cost where you buy it. Answer those two and the comparison is arithmetic. This page answers them in order, states the assumptions openly, and then shows the result at several annual mileages so you can see how the answer scales. Where the page leaves something out — purchase price, depreciation, insurance, servicing and tax — it says so by name.

The short answer is that the comparison comes down to cost per mile: the petrol car burns US gallons, so its cost per mile is the price per gallon divided by its MPG, while the EV uses kilowatt-hours, so its cost per mile is the electricity price per kWh divided by its miles per kWh. With the example assumptions on this page — petrol at $3.45 per US gallon, 32 US MPG, electricity at 31 cents per kWh and 3.5 miles per kWh — the petrol car costs about $0.11 per mile and the EV about $0.09 per mile. Those are example figures, not prices you should quote, and the rest of this page shows how they were reached and what would change them.

Assumptions used on this page for how many miles to break even on an ev

Taking how many miles to break even on an ev as the case in point: Every figure in the tables below comes from this assumptions table. Each one is an assumption or an example, not a measured fact about any particular car or a current price. Substitute your own numbers and the method still works.

Input Value used Status
Petrol price $3.45 per US gallon Example price
Petrol efficiency 32 US MPG Assumption
Electricity price 31 cents per kWh Example price
EV efficiency 3.5 miles per kWh Assumption
Annual mileage 15,000 miles Example

how many miles to break even on an ev: How the EV versus petrol comparison works

Hold the mileage constant and price the energy each car actually uses. For the petrol car, cost per mile equals the price per gallon divided by its MPG. For the EV, cost per mile equals the price per kWh divided by its miles per kWh. Multiply each cost per mile by the annual mileage and you have the annual fuel and charging bill for each car; subtract one from the other and you have the saving, or the extra cost, under those assumptions. The method is deliberately simple, because a simple method with honest inputs beats a complicated model built on guessed ones. The two numbers that matter most are the electricity price and the petrol car's MPG: a driver who charges at home on a cheap overnight rate will see a very different answer from a driver who relies on public rapid chargers, and a thirsty petrol car widens the gap while an efficient one narrows it. That is the point this page works through for how many miles to break even on an ev.

how many miles to break even on an ev: Worked example: the same distance, two energy bills

Take a driver covering 15,000 miles a year. The petrol car does 32 MPG and petrol costs $3.45 per gallon as an example price, so its cost per mile is $3.45 ÷ 32 = $0.11, and 15,000 miles cost $1,617.19 a year. The EV does 3.5 miles per kWh and electricity costs 31 cents per kWh as an example price, so its cost per mile is $0.31 ÷ 3.5 = $0.09, and 15,000 miles cost $1,328.57 a year. The difference on fuel and charging alone is $288.62 a year in the EV’s favour under these assumptions. Now change one input and watch the answer move: if the EV is charged mostly at a public rapid charger at, say, double the home electricity price used here, its annual charging cost doubles and most of the saving disappears. If the petrol car is driven mainly in town at lower MPG, the petrol bill rises and the saving grows. That sensitivity is the real lesson — the answer is only as solid as the assumptions, so write yours down before you believe the result.

how many miles to break even on an ev: Cost at different annual mileages

The table uses the worked-example assumptions above — petrol at $3.45 per gallon (example), 32 MPG, electricity at 31 cents per kWh (example), 3.5 miles per kWh. The gap grows with mileage, which is why high-mileage drivers see the biggest fuel-cost difference and low-mileage drivers see the smallest.

Annual miles Petrol cost per year EV charging cost per year Difference
6,000 $646.88 $531.43 $115.45
8,000 $862.50 $708.57 $153.93
10,000 $1,078.12 $885.71 $192.41
12,000 $1,293.75 $1,062.86 $230.89
15,000 $1,617.19 $1,328.57 $288.62
20,000 $2,156.25 $1,771.43 $384.82

how many miles to break even on an ev: Cost per mile and per 100 miles

At the example assumptions, the petrol car costs $0.11 per mile ($10.78 per 100 miles) and the EV costs $0.09 per mile ($8.86 per 100 miles). Per 100 miles is often the easier figure to compare with a fuel receipt or a charging bill, because both are usually priced in round numbers per hundred miles of driving. If you know your own MPG and your own prices, the same two divisions give your own figures: fuel price per gallon divided by MPG, and electricity price per kWh divided by miles per kWh.

Break-even: how many miles before the EV pays back the price gap for how many miles to break even on an ev

A break-even figure needs one more assumption: the price difference between the two cars. Suppose, as an example only, the EV costs $12,000.00 more than the comparable petrol car. The fuel and charging saving under this page's assumptions is $0.02 per mile, so the break-even distance is $12,000.00 ÷ $0.02 = 623,666 miles. At 15,000 miles a year that is about 41.6 years of driving. That figure counts fuel and charging only. It excludes insurance, depreciation, servicing differences, tyre wear, tax and any grants or incentives — name them, do not hide them — and each one moves the real break-even point. Depreciation alone can outweigh years of fuel savings, and insurance can differ enough to matter. A break-even number that hides those costs is not a like-for-like comparison, so use this page's figure as a starting point and add the excluded items with stated assumptions before deciding anything.

how many miles to break even on an ev: What the comparison leaves out — and why it matters

On this page, how many miles to break even on an ev is the case in point: Treat the saving on this page as a fuel-and-charging figure, not a total-cost verdict. It leaves out the price difference between the cars, depreciation, insurance, servicing, tyres and tax, and it assumes one electricity price when real charging is a blend of cheap home charging and expensive public rapid charging. A driver who charges at home will do better than these figures; a driver who lives on rapid chargers may do worse. Add the excluded items with stated assumptions if you want the full comparison.

how many miles to break even on an ev: Common mistakes

  • On this page, how many miles to break even on an ev is the case in point: Comparing a laboratory test figure against a real-world figure tells you nothing about the car and everything about the methods. Keep the method constant — real-world against real-world — and the comparisons become meaningful.
  • Forgetting that winter changes EV efficiency is easy to miss. Cold weather reduces an EV's miles per kWh noticeably, so a saving calculated on summer figures will overstate the winter result. That is the point this page works through for how many miles to break even on an ev.
  • Taking how many miles to break even on an ev as the case in point: Mixing US and imperial gallons is the biggest, because it shifts the answer by about 20 percent with no warning. A UK imperial gallon is about 4.55 litres; a US gallon is about 3.79 litres, so the same car has a higher MPG figure in imperial gallons than in US gallons.
  • For how many miles to break even on an ev, the point is this: Using one tank or one charge instead of an average is next — a single fill is noisy, and a pump that clicks off early can add a phantom gallon, while a single charge says nothing about your usual mix of home and public charging.

how many miles to break even on an ev: Related calculations

For how many miles to break even on an ev, the point is this: These pages continue from here: the same method on a neighbouring question, or the calculator that runs the arithmetic for you.

how many miles to break even on an ev: Putting your figure to work

Use the result as a tool, not a verdict. Re-run the two divisions with your own prices and efficiencies whenever they change, and the comparison stays honest. A monthly log — miles, energy used, price paid — is enough to spot the patterns that matter: colder months cost more per mile for an EV, a new charging habit shifts the average, and a petrol car driven more in town drifts the other way. Measured figures beat remembered ones, and the method on this page is built for measured figures. That is the point this page works through for how many miles to break even on an ev.

Frequently asked questions

How many kWh does it take to charge an EV?

For how many miles to break even on an ev, the point is this: It depends on the battery size and how empty it is. A charge from near-empty to full takes roughly the battery's capacity in kWh, plus a few percent for charging losses. Divide the kWh drawn by the miles driven afterwards and you have the car's real miles per kWh for that period.

How sensitive is the saving to the electricity price?

On this page, how many miles to break even on an ev is the case in point: Very sensitive. Doubling the electricity price doubles the EV's charging cost per mile, while the petrol side is unchanged. That is why this page states its example prices openly: change the electricity price to the one you actually pay and the saving changes with it, sometimes by enough to change the conclusion.

Why do EV running-cost figures disagree so much?

For how many miles to break even on an ev, the point is this: Because the inputs differ. Two honest calculations can give very different answers if one assumes cheap home charging and the other assumes public rapid charging, or if one uses a high-mileage year and the other a low one. Always ask what electricity price, what MPG and what mileage a figure was calculated with before comparing it with another.

What does miles per kWh mean?

Taking how many miles to break even on an ev as the case in point: It is the EV equivalent of MPG: how many miles the car travels on one kilowatt-hour of electricity. Higher is more efficient. Divide the electricity price per kWh by miles per kWh to get the EV's cost per mile, in the same way you divide the fuel price per gallon by MPG for a petrol car.

What affects an EV's miles per kWh?

Driving speed, temperature, heating and air conditioning, tyre pressures and how much town versus motorway driving you do. Cold weather and high speeds reduce miles per kWh, while gentle town driving usually improves it. Measure yours over several weeks rather than trusting a single trip. That is the point this page works through for how many miles to break even on an ev.