Free Calculators / EV Comparison
An electric car starts 4.1 tonnes behind. When does it catch up?
Building an EV emits more than building a petrol car, almost entirely because of the battery. It then emits less to drive. This works out where those two lines cross — for your grid, your mileage, and your assumptions.
0.274 kgCO₂e per kWh, generation through to well-to-tank
Compare against
The starting position
- Petrol car, manufacturing
- 3.70 t
- EV, manufacturing
- 3.30 t
- EV, battery
- 4.50 t
- EV starts behind by
- 4.10 t
Over 8 years · 59,200 miles
The EV saves 12.74 tCO₂e over that period — 50% lower than the petrol car, manufacturing included.
Per mile, in use
- Petrol — tailpipe
- 0.287 kg
- Petrol — well-to-tank
- 0.080 kg
- Electric — grid, all scopes
- 0.082 kg
- Saved per mile
- 0.284 kg
And the money
The same miles, priced.
Same mileage, years and consumption as above. Pump prices are the UK weekly average from the Department for Energy Security and Net Zero; electricity is the Ofgem cap and the Zapmap public-charging index; the purchase premium is the average across five cars sold in both electric and combustion form. Every figure is editable.
Who is buying?
A company car adds benefit-in-kind tax for the driver and Class 1A National Insurance for the employer. For most fleets this outweighs the fuel.
Per year · 7,400 miles
| Petrol | Electric | EV saves | |
|---|---|---|---|
| Per mile, in use | 19.3p | 10.9p | 8.4p |
| Fuel or electricity | £1,431 | £806 | £625 |
| Running cost per year | £1,431 | £806 | £625 |
Electricity blended at 36.3p a kWh from your home and public split. Servicing, tyres, insurance and depreciation are not included: the first two favour the EV, the last two are argued over, and none of them is the size of the fuel line.
Out of the dealership
Five cars sold in both forms, cheapest trim of each, manufacturer list price before discounts. Checked 7 Sept 2026.
| Model | Petrol | Electric | Grant | Premium |
|---|---|---|---|---|
| Vauxhall Corsa | £20,590 | £27,505 | −£1,500 | £5,415 |
| Peugeot 208 | £20,495 | £24,995 | −£1,500 | £3,000 |
| Peugeot 2008 | £25,650 | £29,495 | −£1,500 | £2,345 |
| Vauxhall Mokka | £26,545 | £32,189 | −£1,500 | £4,144 |
| Hyundai Kona | £27,205 | £32,400 | −£3,750 | £1,445 |
| Average | £24,097 | £29,317 | £3,270 |
Premium is after the Electric Car Grant, which every car here qualifies for. Before it, the average gap is £5,220. Trims are matched as closely as the ranges allow, not identically; the electric version usually carries more kit.
Method & sources
What is counted
Manufacturing for both vehicles, the battery separately, and every mile driven. Fuel includes combustion at the tailpipe plus the emissions of extracting and refining it. Electricity includes generation, transmission and distribution losses, and the well-to-tank emissions of both — not just the grid figure, which would understate it by around a third.
What is not
Servicing, tyres, brake and road particulates, and end-of-life treatment. Battery second life and recycling are excluded, which is conservative: both would move the result in the EV’s favour. Vehicles are the dataset’s “medium car” class throughout.
Factors
UK Government (DEFRA) 2023 conversion factors for fuel and electricity, and IEA lifecycle assessment figures for manufacturing. Grid factors are location-based; a renewable tariff is a market-based claim and does not change the physical electricity a car draws.
Prices
Pump prices are the UK weekly average published by the Department for Energy Security and Net Zero, fetched live and cached for a day. Home electricity is the Ofgem price cap unit rate for the current quarter; public charging is the Zapmap Price Index for the latest month. List prices are manufacturer RRPs from carwow, grant bands from the DfT Electric Car Grant list. Company car tax uses 2026/27 appropriate percentages and 15% Class 1A National Insurance. VED, insurance, servicing and depreciation are excluded.
The honest caveat
Grid factors are a snapshot. Most electricity systems are decarbonising, so an EV bought today gets cleaner every year it is driven, while a combustion car does not. This model holds the grid constant, which understates the EV case over a long ownership period.