About the data

The catalogue

The site currently covers 13 models and 23 trims, entered by hand. List prices, battery sizes, efficiency, fuel economy, CO₂ figures and insurance groups are illustrative rather than quoted from a licensed source. A licensed vehicle data feed is on the roadmap and will replace the hand-curated list when it lands.

What goes into a cost

Every option is costed over its ownership period and shown per year so that different finance terms compare fairly. The lines that make it up:

Vehicle

For cash, the depreciation between buying and selling, from a curve per powertrain (or per model where known). For PCP, lease, HP and salary sacrifice, the payments from your quote. HP also credits the car’s residual value at the end, because you own it.

Energy and fuel

Electricity from the car’s efficiency, your mileage and your home/public split; fuel from its mpg. Plug-in hybrids are assumed to cover 45% of miles on electricity.

Tax (VED)

UK vehicle excise duty: the first-year rate by CO₂ band, then the standard rate, plus the expensive-car supplement in years two to six for cars listed at £40,000 or more.

Insurance

A monthly estimate by insurance group, anchored to the ABI’s average comprehensive premium and scaled by group. Real premiums vary widely, so you can override it per car.

Maintenance

Tyres, servicing and MOT, and unexpected repairs, as UK estimates per powertrain that rise with the car’s age over the years you own it. Each part can be overridden.

Salary sacrifice

The gross sacrifice less income tax and National Insurance at your band, plus Benefit-in-Kind tax on the car. Tax, insurance and maintenance are assumed to be bundled in the scheme.

Default assumptions

Typical UK figures, all editable in the “Your driving” step or from the results page.

Annual mileage

10,000 miles

Home electricity

7p / kWh

Public charging

60p / kWh

Charged at home

80%

Petrol

156p / litre

Diesel

186p / litre

Breakdown cover

£60 / year

Income tax band

40%

Opportunity cost

Off by default (5% / year when on)

Opportunity cost adds the investment return you give up on deposits, cash purchases and monthly payments. It is off by default because the right rate is a judgement call.