United Kingdom version
How it works
Compare an EV purchase-price difference with energy and maintenance scenarios for equal annual driving.
This is the United Kingdom planning view, with monetary inputs and outputs in GBP. A currency label does not establish that a tax rate, construction price, coverage rule or legal limit has been verified locally. The inputs and limitations below describe the actual scope.
Input query strings and outputs
Use an input name in this page’s URL as ?name=value, and join additional inputs with &. Portable shared links may instead use the compact ?ac= state parameter.
Input query strings
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?unitSystem=Measurement systemChoice · Optional · Default: metric · Accepted values: imperial, metric
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?annualDistance=Annual driving distanceNumber · Required · Default: 20,000
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?evConsumption=Vehicle battery consumptionNumber · Required · Default: 18
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?chargeEfficiency=Wall-to-battery charging efficiencyPercentage · Required · Default: 90
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?electricityRate=Electricity price per wall kWhMoney · Required · Default: 0.2
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?fuelConsumption=Comparison fuel consumptionNumber · Required · Default: 7
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?fuelPrice=Fuel price per volume unitMoney · Required · Default: 1.6
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?evPurchase=EV purchase price after confirmed incentivesMoney · Required · Default: 40,000
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?fuelPurchase=Comparison vehicle purchase priceMoney · Required · Default: 30,000
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?evMaintenance=Annual EV maintenance assumptionMoney · Required · Default: 500
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?fuelMaintenance=Annual comparison maintenance assumptionMoney · Required · Default: 800
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?years=Comparison horizon, yearsNumber · Required · Default: 8
Outputs
6-
evEnergyCostAnnual EV energy spendingCurrency · Currency: GBP
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fuelEnergyCostAnnual comparison fuel spendingCurrency · Currency: GBP
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extraCapitalExtra EV purchase costCurrency · Currency: GBP
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annualSavingAnnual energy and maintenance savingCurrency · Currency: GBP
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paybackSimple purchase-premium payback, yearsNumber
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horizonSavingEnergy/maintenance saving less purchase premiumCurrency · Primary output · Currency: GBP
Formula
annual saving = comparison energy + maintenance − EV energy − maintenance.
Calculations retain numeric precision internally. Displayed values are rounded for readability. Quantities that must be purchased as whole units are rounded up only where the formula explicitly requires it.
Read the inputs before calculating
- Annual driving distance: Enter the quantity described by the label. The measurement selector converts this physical quantity; it does not change the underlying scenario.
- Vehicle battery consumption: Enter the quantity described by the label. The measurement selector converts this physical quantity; it does not change the underlying scenario.
- Wall-to-battery charging efficiency: Enter the quantity described by the label.
- Electricity price per wall kWh: Enter the quantity described by the label.
- Comparison fuel consumption: Enter the quantity described by the label. The measurement selector converts this physical quantity; it does not change the underlying scenario.
- Fuel price per volume unit: Enter the quantity described by the label. This is a price per displayed unit, so the price converts inversely to the physical quantity.
- EV purchase price after confirmed incentives: Enter the quantity described by the label.
- Comparison vehicle purchase price: Enter the quantity described by the label.
- Annual EV maintenance assumption: Enter the quantity described by the label.
- Annual comparison maintenance assumption: Enter the quantity described by the label.
- Comparison horizon, years: Enter the quantity described by the label.
Reproducible worked example
The following is a fictional arithmetic example, not a local quote, a verified claimant or a market forecast. Its values are included so the formula can be checked. The form does not automatically confirm any verification checkbox.
| Input | Example value |
|---|---|
| Annual driving distance (km) | 20,000 |
| Vehicle battery consumption (kWh/100 km) | 18 |
| Wall-to-battery charging efficiency | 90 |
| Electricity price per wall kWh | 0.2 |
| Comparison fuel consumption (L/100 km) | 7 |
| Fuel price per volume unit (/L) | 1.6 |
| EV purchase price after confirmed incentives | 40,000 |
| Comparison vehicle purchase price | 30,000 |
| Annual EV maintenance assumption | 500 |
| Annual comparison maintenance assumption | 800 |
| Comparison horizon, years | 8 |
| Output | Calculated result |
|---|---|
| Annual EV energy spending | GBP 800 |
| Annual comparison fuel spending | GBP 2,240 |
| Extra EV purchase cost | GBP 10,000 |
| Annual energy and maintenance saving | GBP 1,740 |
| Simple purchase-premium payback, years | 5.7471 |
| Energy/maintenance saving less purchase premium | GBP 3,920 |
Interpreting a changed assumption
Start with one complete scenario and change only one input when diagnosing a difference. Recheck units, the period of every rate, whether an amount is recurring or one-off, and whether a cost is already included elsewhere. A larger calculated benefit is not evidence that an assumption is more likely to occur.
Limitations
- Prices, consumption and contract terms are entered scenarios. This is not a retail quote, tax eligibility determination or vehicle safety certification.
- This is not total ownership cost: resale value, financing, insurance differences, charging installation and taxes need separate scenarios. A zero purchase premium does not guarantee lower lifetime cost.
Frequently asked questions
What does this EV Versus Petrol Cost result represent?
Compare an EV purchase-price difference with energy and maintenance scenarios for equal annual driving. It applies the displayed formula to your inputs; it does not infer omitted facts.
Are the starting amounts verified United Kingdom prices or legal rules?
No. Numeric defaults are illustrative unless an input or dated reference explicitly identifies a researched component. Currency is GBP; local quotes, eligibility and unsupported rules must be entered and verified separately.
What must I check before relying on the result?
Prices, consumption and contract terms are entered scenarios. This is not a retail quote, tax eligibility determination or vehicle safety certification.
Can I compare or share different assumptions?
Change one assumption at a time and use the browser-local project or share controls. A shared URL contains the encoded input values; do not include information you do not wish to disclose.
Sources and reference scope
- DOE energy-use arithmetic — retrieved 2026-09-24. Energy consumption versus power; not a local tariff or an approval of this implementation.
- NIST unit conversion guidance — retrieved 2026-09-24. Unit definitions; geometry and financial arithmetic in these worksheets are explicitly stated.
- CFPB loan-estimate explanation — retrieved 2026-09-24. US cost components; the general amortization formula is stated separately.
These references support only their stated scope. They are not evidence that every local rule or price needed by the master expansion has been loaded.