Electric wins per mile
Home charging will normally undercut petrol substantially, particularly on a genuine overnight tariff.
EV costs without the sales pitch
Is an EV worth it for a high-mileage driver who hates finance?
Electricity can cost far less per mile than petrol. That does not automatically make an expensive electric car cheaper than a reliable car you already own outright.
UK figures and policy checked: 22 September 2026
A real high-mileage dilemma
The cheapest car can be the one already on the drive.
My own position makes a useful example. I drive more than 30,000 miles a year for work. My petrol car cost £1,800 outright and returns roughly 37–41mpg. It is not especially economical to fuel, but there is no lease, no finance agreement and very little value left to lose through depreciation.
A used long-range EV could cut the energy cost of those miles. It would also require far more money upfront—or a lengthy financial commitment that still has to be paid if the work disappears. For a self-employed driver, that risk belongs in the calculation.
The paid-for car starts ahead
An £1,800 car cannot depreciate by another £15,000. Replacing it creates a purchase premium that fuel savings must recover.
Debt changes the decision
A finance payment is due in good months and bad. Financial resilience can be more valuable than the lowest theoretical cost per mile.
Three honest routes
This is not simply “petrol or electric”.
1. Keep the paid-for petrol car
Best when: capital is tight, journeys are unpredictable or the current car remains dependable.
You pay more for every mile, but preserve cash, avoid finance and retain complete journey flexibility.
2. Replace it with one long-range EV
Best when: the car can cover virtually every working day and the purchase premium can be recovered without financial strain.
This removes duplicate fixed costs, but places every journey—including winter motorway days—on the EV and charging network.
3. Add a modest used EV
Best when: enough local mileage can move to the EV while the petrol car covers long and unpredictable work.
This can offer cheap local miles without range anxiety, but only if the mileage saving exceeds the second car's insurance, tax, upkeep and depreciation.
Interactive comparison
Would a second EV actually pay in your case?
Enter the figures you genuinely expect. The calculator compares the petrol cost of the mileage transferred to an EV with charging, the EV's additional annual costs and its depreciation over your chosen ownership period.
Cheap petrol car versus a used EV for suitable journeys
Supplier examples checked 22 September 2026. Eligibility, peak rates, standing charges and regional prices also matter.
All private and work mileage.
Journeys it can complete without inconvenient public charging.
Use a real long-term figure.
UK E10 average from 7,854 open forecourts in the published data supplied 22 September 2026.
Use a cautious winter-aware average.
Insurance, VED, MOT, servicing and repair allowance—not electricity.
Set to zero for a comparison before the planned April 2028 charge.
EV-suitable miles—
Petrol cost avoided—
EV annual cost—
Annual difference—
Enter your figures to see the result.
Illustration only. The result excludes finance interest, charger installation, solar generation, public charging, major faults, opportunity cost and differences in insurance excess. It treats purchase price minus resale value as straight-line depreciation.
The 7kW reality
A cheap overnight rate is only useful if enough energy can be delivered.
A typical single-phase 7kW home charger can theoretically deliver about 42kWh in a six-hour window. Real charging is not perfectly lossless and the car may not draw its maximum rate throughout, but that is still enough for roughly 120–150 miles in many EVs.
It is not enough to refill every large 70kWh battery from empty. For most drivers that does not matter because they do not arrive home empty every night. For a high-mileage worker, however, the daily journey pattern—not the headline battery capacity—decides whether a six-hour tariff window works.
Do not solve the wrong problem with three-phase power.
An 11kW charger normally requires a three-phase supply. Before accepting that expense, test whether ordinary 7kW overnight charging, occasional daytime top-ups and the car's real daily energy use already cover the requirement.
Buying a used local EV
Low mileage is not the same as a healthy battery.
| Check | Why it matters | Practical rule |
|---|---|---|
| Battery state of health | Remaining usable capacity determines real range. | Require a diagnostic report, not just dashboard range. |
| Winter motorway range | Cold weather, heating and speed reduce range together. | Plan around the difficult day, not the advertised maximum. |
| Cell balance and faults | An apparently healthy average can hide a weak module. | Use an EV specialist or model-specific diagnostic tool. |
| Rapid-charging connector | Older Leafs use CHAdeMO while most newer UK installations favour CCS. | Buy a Leaf principally for home-charged, predictable journeys. |
| Insurance quote | A cheap purchase can still carry an unexpectedly high premium. | Quote the exact registration before travelling to buy. |
| Warranty | Age and mileage limits may be near even on a low-mileage car. | Verify remaining cover in writing. |
Where solar fits
An EV can transform a home's electricity demand—but solar does not automatically fuel every mile.
A high-mileage EV can consume several thousand additional kilowatt-hours each year. Solar may supply part of that demand when the car is home during daylight, while a smart charger can follow genuine surplus generation.
If the car is away all day, cheap overnight grid charging may do most of the work. A home battery can move some solar into the evening, but repeatedly sending grid or solar energy through a small home battery before putting it into a much larger car battery adds losses and cycling.
The solar array, home battery, charger, tariff and travel pattern should therefore be modelled as one energy system.
The honest conclusion
Cheaper per mile does not always mean cheaper overall.
For a driver buying one vehicle from scratch, high mileage can make an EV compelling. For someone who already owns a serviceable £1,800 petrol car, the decision is harder. The EV must recover its purchase premium without creating unacceptable debt, range limitations or duplicate costs.
A modest used EV alongside the petrol car can be a sensible bridge—but only when enough suitable mileage transfers to it. If the calculator shows that the second car merely shifts spending from petrol into depreciation, insurance and tax, the financially sound answer is to keep the car already paid for.
The decision threshold is personal:
Buy when the car covers the work, the battery has been independently checked, the numbers survive cautious assumptions and the purchase leaves your financial safety margin intact.
Sources and assumptions
Useful official checks
- GOV.UK: vehicle tax for electric and low-emission vehicles
- GOV.UK: proposed Electric Vehicle Excise Duty mileage charge
- Dundee City Council: current Low Emission Zone rules
Prices, tariffs, tax policy, vehicle values and charging availability change. This page provides an illustration, not personal financial or vehicle-purchase advice. Verify current rules and obtain model-specific inspections and quotations before committing money.
Plan the whole home
Considering solar, a battery or EV charging?
A proper assessment should use your roof, household consumption, travel pattern, charger and tariff—not a generic national average.