EV vs Petrol Cost Calculator

Compare what you would spend on fuel against electricity each year and over the years you keep the car.

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Updated 4 Nov 2026

Miles a year

miles

Years you'll keep it

years

Petrol or diesel car

MPG

Fuel price

p/litre

Electric car

Efficiency

Charged at home:

Home price

p/kWh

Public price

p/kWh

Losses

Home: Ofgem price cap, 1 October to 31 December 2026 (GB average, Direct Debit). Public: rapid average, Zapmap Price Index, September 2026 (pay-as-you-go averages).

Extra cost to buy the EV

Enter a negative number if the EV is cheaper to buy.

Other yearly costs: petrol

Other yearly costs: EV

For example servicing, insurance or clean air zone charges. Vehicle tax is usually the same £200 for both.


EV per year
Energy cost per mile

Break-even

Running total

Electric

How to use the ev vs petrol cost comparison

1 Enter your annual mileage and how many years you expect to keep the car.
2 Enter the petrol or diesel car's MPG and the fuel price.
3 Enter the EV's efficiency and how much of your charging happens at home compared with public chargers.
4 Optionally add the extra purchase cost of the EV and other yearly costs to see when, or if, it pays back.

Worked example

10,000 miles a year

Petrol car: 45 MPG at 172.8p
EV: 30 kWh/100 miles, 10% losses
Charging: 80% home at 26.32p, 20% rapid at 79p

Petrol: 1,010 litres. EV: 3,333 kWh at the plug, 80/20 split

= Petrol £1,745 a year, EV £1,229 a year: about £517 a year or £2,585 over 5 years in the EV's favour

Assumptions and limitations

Compares energy costs only unless you add other costs. Purchase price, depreciation, finance and insurance are excluded unless you enter them.
Prices stay flat for the whole period. Fuel and electricity prices will change.
Default fuel price: UK average pump prices, week commencing 2 November 2026 (DESNZ weekly road fuel prices). Electricity: Ofgem price cap, 1 October to 31 December 2026 (GB average, Direct Debit); public rapid: Zapmap Price Index, September 2026 (pay-as-you-go averages).
Cars first registered from 1 April 2017 pay the same £200 standard rate of vehicle tax whether electric or petrol, so VED is not a difference for most comparisons.

What decides whether an EV is cheaper to run

Three numbers do most of the work: how many miles you drive, how efficient each car is, and what you pay for electricity. A driver who charges overnight on a cheap tariff can cut energy costs by more than half compared with petrol. A driver who relies on rapid chargers may pay about the same per mile as a petrol car, or more.

Set the home charging share honestly. If you cannot charge at home, set it to zero and use a realistic public price.

The price gap and break-even

Electric cars often cost more to buy, so lower running costs have to repay the difference. Enter the extra cost and the calculator shows how many years of driving it takes to break even at your mileage. Low-mileage drivers may never break even on energy savings alone.

Depreciation can outweigh both. Use the depreciation calculator and the running cost calculator for the full picture.

Tax, servicing and charges

Electric cars have paid vehicle tax since 1 April 2025, and cars registered from 1 April 2017 now pay the same standard rate whatever the fuel. Servicing is often a little cheaper on an EV, and an electric car is exempt from London's ULEZ charge. Add any of these in the other yearly costs fields to include them.

Official guidance and sources

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All free tools

EV Charging Cost Calculator What a charge costs at home, on an off-peak tariff or at a rapid charger, with losses and cost per mile. Car Running Cost Calculator Fuel, tax, MOT, servicing, insurance, parking and finance added up per month, per year and per mile. Car Depreciation Calculator Low, base and high estimates of a car's future value from price, age, mileage and type. Not a valuation.

Frequently Asked Questions

Usually, if you can charge at home. At 10,000 miles a year, a 45 MPG petrol car uses about £1,745 of fuel at 172.8p a litre, while an EV using 30 kWh per 100 miles and charging 80% at home on the price cap costs about £1,229. Relying on rapid chargers narrows or reverses the gap.

The electric equivalent of litres per 100km: how much energy the car uses to drive 100 miles. Lower is better. 30 kWh/100 miles is the same as 3.33 miles per kWh. You can enter the EV's efficiency either way in the calculator.

Yes. Since 1 April 2025 electric cars pay vehicle tax. Those registered from 1 April 2017 pay the same £200 standard rate as petrol and diesel cars from the second year, and the expensive car supplement applies to EVs with a list price over £50,000.

Enter the extra purchase cost in the price difference field. The calculator adds it to the EV's running total and shows the year in which the cumulative cost lines cross, if they do within your ownership period.

Not by default, because they vary so much by model and driver. Add yearly insurance, servicing or other costs for each car in the optional fields, and use the depreciation calculator separately for resale value.

Figures and guidance last checked 4 November 2026. An independent free tool from Free Car Tax MOT Check; not affiliated with DVLA, DVSA or GOV.UK. Results are estimates to help you plan, not financial, legal or mechanical advice.