EV vs Petrol Cost Calculator

Last updated: April 2026

Vehicle details

Annual mileage7,400 miles/year

Fuel typeFuel efficiency

mpg

Fuel price

p/litre

Petrol/diesel purchase price

GBP

EV purchase price

GBP

Home charging rate

p/kWh

Public charging rate

p/kWh

Petrol or diesel costs

ServicingInsuranceRoad tax

EV costs

Miles per kWhServicingInsuranceRoad tax

From April 2025, EVs pay standard VED for most cars. Adjust the road tax field if your vehicle differs.

Charging mix

Annual cost comparison

Metric	Petrol	Diesel	EV
Annual fuel	£1,219	£1,029	£710
Annual total	£2,609	£2,419	£1,950
vs EV saving	£659	£469	--
CO2/year	1,262kg	1,246kg	493kg

Cost	petrol	EV
Fuel cost	£1,219	£710
Servicing	£400	£150
Insurance	£800	£900
Road tax	£190	£190
Annual total	£2,609	£1,950

Annual saving: £659

Payback

EV purchase premium: £10,000
Annual saving: £659
Payback period: 15.2 years

5-year total cost

Petrol/diesel total: £38,047
EV total: £44,752
You save: -£6,705

Years to compare

CO2 saving

765 kg CO2/year

Equivalent to about 36 trees absorbing carbon for a year.

Cumulative cost chart

Petrol/dieselEVNo crossover in this period

Charging sensitivity

Charging mix	Annual EV fuel cost
Home only	£518/year
Mostly home	£710/year
Mix 50/50	£999/year
Mostly public	£1,191/year
Public only	£1,480/year

Is an electric car cheaper to run than petrol in the UK?

For most UK drivers who can charge at home, an electric car is significantly cheaper to run than an equivalent petrol car. The gap narrows for drivers who rely heavily on public rapid charging.

What is the total cost of ownership for an EV?

EVs typically cost more to purchase than equivalent petrol cars, but have lower running costs: cheaper fuel, lower servicing costs and, from April 2025, broadly the same road tax as petrol cars.

How much does it cost to charge an EV at home?

Charging at home on a standard tariff costs around 24.5p per kWh. A typical EV travels around 3.5 miles per kWh, giving a home charging cost of roughly 7p per mile. EV-specific overnight tariffs can reduce this further.

About this calculator

The EV vs Petrol Cost Calculator compares the running cost of an electric vehicle with a petrol or diesel vehicle. It estimates fuel or electricity cost, efficiency, mileage, tax, servicing, insurance, depreciation, charging losses, and potential home or public charging mixes. Use this expanded guide when you need more than a quick result. It explains the assumptions behind the EV vs Petrol Cost Calculator, the records to gather, and the decisions the estimate can support. It is especially useful for drivers comparing electric, petrol, diesel, or hybrid running costs before buying, leasing, or switching tariffs. The strongest use of the page is scenario comparison: change one input at a time, compare the output, and keep a note of which assumption changed.

EV versus petrol method

The calculator estimates annual energy cost for each vehicle and then adds other ownership costs to compare total cost. The calculator result depends on the quality of the inputs and on the rule set or formula selected in the calculator above. For practical use, treat the output as a structured estimate: start with the core inputs, review the main outputs, then test the decision points that matter most to your situation. Key decisions include whether lower EV energy cost offsets purchase price, how home versus public charging changes cost, whether mileage is high enough to matter.

EV electricity cost = miles x kWh per mile x electricity price
petrol cost = miles / mpg x fuel price per gallon
total cost = energy + tax + insurance + servicing + depreciation
better estimate = accurate inputs + correct rule set + realistic assumptions
scenario difference = revised result - original result

How to use the EV comparison calculator

Enter annual mileage.
Enter EV efficiency and electricity rates for home and public charging.
Enter petrol or diesel MPG and fuel price.
Add insurance, servicing, tax, depreciation, and finance if available.
Review annual and multi-year cost difference.
Gather the main inputs first: annual mileage, EV efficiency, charging mix.
Check supporting records such as fuel receipts and electricity tariff before relying on a final number.
Enter one realistic scenario first, using conservative assumptions where the future is uncertain.
Review the main outputs: annual energy cost, cost per mile, total ownership cost.
Run at least one alternative scenario so you can see which input changes the answer most.
Compare the result with vehicle manufacturer data, tariff information, and fuel price records or the relevant contract, bill, statement, or professional document.
Keep the calculation date and assumptions with your notes so you can revisit the estimate when rates, rules, or circumstances change.

Worked example

Electricity running cost

Input: 8,000 miles, 0.28kWh per mile, electricity 15p/kWh

Calculation: 8,000 x 0.28 x GBP0.15 = GBP336

Result: Estimated annual EV energy cost is GBP336 before charging losses.

Home-charging scenario

Input: Most charging is at a low overnight rate.

Calculation: EV kWh use is multiplied by the lower home rate for most miles.

Result: The EV running-cost advantage is stronger.

Rapid-charging scenario

Input: A driver relies on public rapid charging for half of miles.

Calculation: A higher public-charging rate is blended into the average electricity cost.

Result: The cost gap versus petrol narrows.

Charging mix matters

EV savings are strongest when most charging is done at a lower home or off-peak rate. Frequent rapid public charging can narrow or remove the saving compared with an efficient petrol or hybrid vehicle.

What to check before relying on the result

A useful EV vs Petrol Cost Calculator result starts with the same evidence you would use if you were checking the answer manually. The calculator can organise the arithmetic, but it cannot know whether a payslip is final, a bill is estimated, a quote excludes fees, or a personal circumstance has changed since the last statement.

Before making a decision, compare the calculator result with the source document that controls the real outcome. For this topic, that usually means checking vehicle manufacturer data, tariff information, and fuel price records. If there is a difference between the calculator and an official statement, contract, assessment, or professional advice, treat the official document as the stronger source.

fuel receipts: Use this as supporting evidence for the calculation. If it is out of date, estimated, or based on a different period, the calculator output may look precise while still being wrong for the decision.
electricity tariff: Use this as supporting evidence for the calculation. If it is out of date, estimated, or based on a different period, the calculator output may look precise while still being wrong for the decision.
vehicle efficiency figures: Use this as supporting evidence for the calculation. If it is out of date, estimated, or based on a different period, the calculator output may look precise while still being wrong for the decision.
insurance quote: Use this as supporting evidence for the calculation. If it is out of date, estimated, or based on a different period, the calculator output may look precise while still being wrong for the decision.
finance quote: Use this as supporting evidence for the calculation. If it is out of date, estimated, or based on a different period, the calculator output may look precise while still being wrong for the decision.

Inputs that usually change the answer

The most important input is not always the largest number on the form. Sometimes a date, threshold, percentage, eligibility flag, or timing assumption changes the result more than the headline amount. This is why scenario testing is more useful than a single calculation.

Input	Why it matters	What to double-check
annual mileage	It feeds directly into the estimate or changes which rule is applied.	Check the period, units, eligibility, and whether the figure is final or estimated.
EV efficiency	It feeds directly into the estimate or changes which rule is applied.	Check the period, units, eligibility, and whether the figure is final or estimated.
charging mix	It feeds directly into the estimate or changes which rule is applied.	Check the period, units, eligibility, and whether the figure is final or estimated.
electricity rates	It feeds directly into the estimate or changes which rule is applied.	Check the period, units, eligibility, and whether the figure is final or estimated.
petrol or diesel MPG	It feeds directly into the estimate or changes which rule is applied.	Check the period, units, eligibility, and whether the figure is final or estimated.

How to interpret the output

The output should be read as a decision aid, not just a number. For EV vs Petrol Cost Calculator, the useful question is often what the result means for timing, affordability, eligibility, comparison, or next steps.

annual energy cost: Use this output alongside the other results rather than in isolation. A monthly amount, percentage, date, or payback figure can look acceptable until fees, timing, evidence, or eligibility conditions are added.
cost per mile: Use this output alongside the other results rather than in isolation. A monthly amount, percentage, date, or payback figure can look acceptable until fees, timing, evidence, or eligibility conditions are added.
total ownership cost: Use this output alongside the other results rather than in isolation. A monthly amount, percentage, date, or payback figure can look acceptable until fees, timing, evidence, or eligibility conditions are added.
break-even comparison: Use this output alongside the other results rather than in isolation. A monthly amount, percentage, date, or payback figure can look acceptable until fees, timing, evidence, or eligibility conditions are added.

Scenarios worth comparing

A single estimate is a snapshot. A better approach is to save a base case, then adjust one assumption at a time. This shows whether the result is stable or whether a small change in timing, rate, usage, income, or cost creates a very different answer.

Scenario	Change one assumption	What the comparison shows
Base case	Use the best current evidence.	Shows the result you would expect if nothing important changes.
Conservative case	Use lower income, higher cost, slower growth, or less favourable timing.	Shows whether the decision still works with less optimistic assumptions.
Improved case	Use the realistic upside, such as lower cost, better rate, higher usage, or stronger evidence.	Shows the potential benefit without treating it as guaranteed.

Common mistakes and edge cases

Most errors come from using the right formula with the wrong assumption. Dates can be counted differently, rates can change, official thresholds can move, and real bills or contracts often include conditions that a simple calculator cannot infer automatically.

Public rapid charging can be expensive.: Check this point before using the estimate for a payment, claim, purchase, application, employment decision, or health-related decision.
Winter driving can reduce EV efficiency.: Check this point before using the estimate for a payment, claim, purchase, application, employment decision, or health-related decision.
Depreciation can dominate total cost.: Check this point before using the estimate for a payment, claim, purchase, application, employment decision, or health-related decision.
Home charging access changes the calculation.: Check this point before using the estimate for a payment, claim, purchase, application, employment decision, or health-related decision.

Next steps after calculating

Once you have a result, write down the key assumptions and compare them with vehicle manufacturer data, tariff information, and fuel price records. If the number affects a deadline, tax return, benefit claim, employment issue, medical question, finance agreement, or major purchase, use the calculator as preparation for a more formal check.

For lower-stakes use, the next step may simply be comparing two or three scenarios. For higher-stakes use, the next step should be checking the official guidance, speaking to the relevant organisation, or getting qualified advice before acting.

Important edge cases

Public rapid charging can be expensive.
Winter driving can reduce EV efficiency.
Depreciation can dominate total cost.
Home charging access changes the calculation.

Limitations

This calculator is a general estimate only and is not vehicle or financial advice. This is general vehicle-cost information and not financial advice. The calculator is designed to support understanding and planning, but it cannot verify documents, predict future rule changes, or account for every exception. Use it as an estimate and check the official source before acting where the result matters.

Real efficiency changes with weather, speed, tyres, and driving style.
Depreciation can dominate total ownership cost.
Tax, insurance, and charging prices can change.
Check vehicle manufacturer data, tariff information, and fuel price records for current rules, rates, definitions, and eligibility where relevant.
Do not rely on a single scenario where income, costs, dates, rates, usage, or health circumstances may change.
Keep records of the inputs used so that the estimate can be reviewed later.

Frequently asked questions

Is an EV always cheaper to run?

Not always. It depends on electricity price, charging mix, mileage, vehicle price, and depreciation.

Should public charging be included?

Yes. Public rapid charging can be much more expensive than home charging.

Does winter affect EV cost?

Often yes. Cold weather can reduce efficiency and range.

Should depreciation be included?

Yes for total ownership cost, because fuel saving alone can be outweighed by purchase-price or resale differences.

Is MPG reliable?

Real-world MPG can differ from official figures, so use your own fuel history where possible.

Does road tax change the result?

It can. Include vehicle tax or equivalent charges for the period being compared.

Related calculators

EV Charging Cost Calculator
Auto Loan Calculator
Auto Lease Calculator
Electricity Cost Calculator

What does this mean?

This calculator is designed to help you understand the likely number before you make a decision or start an application.

Your result should be checked against official UK guidance, especially if your circumstances include dependants, exemptions, prior leave, or a complex immigration history.

Treat the figure as a planning tool rather than legal advice. Where the answer affects an application deadline or major payment, speak to an authorised adviser.