Compare cars: running costs side by side
Pick two or three new cars to compare official mpg or miles per kWh, CO2, yearly fuel or electricity cost and road tax. 532 entries from the Vehicle Certification Agency's data, priced at October 2026 rates.
Choose your cars
Type a make or model to search. Costs start at 10,000 miles a year and the dated prices below; change any of them to match how you drive. For ranked lists, see the cheapest cars to run.
Default prices
What the tool uses until you change it. Standard road tax is £200 a year for every car here, including electric.
- Petrol
- 174.88p a litre
- Week of 5 October 2026
- Diesel
- 199.52p a litre
- Week of 5 October 2026
- Electricity
- 26.32p a kWh
- Price cap, 1 October to 31 December 2026
- Distance
- 10,000 miles a year
- Same for every car
- Road tax
- £200 a year
- Standard rate, 2026/27
Method and limitations
Yearly cost is your miles divided by the official combined mpg (or miles per kWh), times the price of fuel or electricity. Total a year adds the standard road tax.
- Official WLTP figures are from the laboratory. The VCA says they may not be achieved in real-world driving.
- The list covers cars currently on sale, grouped by model, fuel and engine size. Plug-in hybrids and performance sub-brands are not included.
- Insurance, servicing, tyres and depreciation are not included.
- Electric costs use whatever electricity price you enter. Public charging usually costs more than home charging.
- An extra £440 a year applies for five years to cars with a list price over £40,000 (over £50,000 for electric cars), so the standard rate understates tax on those cars.
Sources
- Vehicle Certification Agency: Car fuel data, CO2 and vehicle tax tools
Official WLTP combined mpg, miles per kWh and CO2 for new cars on sale. Latest data file downloaded 8 October 2026.
- DESNZ weekly road fuel prices (GOV.UK)
Petrol 174.88p and diesel 199.52p a litre, week of 5 October 2026.
- Ofgem energy price cap unit rates
Electricity 26.32p a kWh, average Direct Debit rate for 1 October to 31 December 2026.
- GOV.UK vehicle tax rates
Standard rate £200 a year for cars registered on or after 1 April 2017, 2026/27. Checked 8 October 2026.
Buying used? Check the car's history first
Official figures describe a new car. A used one also has a past: outstanding finance, write-off records, stolen markers and mileage that may not add up. Enter the registration to see them before you hand over any money.
Check a used car's history, from £9.99Frequently asked questions
They are the official WLTP combined figures in the Vehicle Certification Agency's car fuel and emissions database, using the latest data file downloaded on 8 October 2026. Manufacturers supply them and the VCA publishes them.
Wheel size, gearbox, battery size and engine tune change a car's official figure. We show the best figure for the model and engine and, in the table, the range across its trims. The cost uses the best figure, so a lower trim can cost more.
Petrol 174.88p and diesel 199.52p a litre (DESNZ weekly road fuel prices, week of 5 October 2026) and electricity 26.32p a kWh (Ofgem price cap, 1 October to 31 December 2026). You can type your own prices and miles.
The tool shows the standard rate of £200 a year (2026/27) that applies from the second payment for cars registered on or after 1 April 2017. An extra £440 a year applies for five years to cars with a list price over £40,000 (over £50,000 for electric cars), so the standard rate understates tax on those cars. The first payment depends on the car's CO2 figure.
No. Insurance group data is not freely available, so the totals cover fuel or electricity and standard road tax only. Servicing, tyres and depreciation are not included either.
Probably not exactly. They come from laboratory tests, and the VCA says they may not be achieved in real-world driving. They are reliable for comparing one car with another, less so for predicting your own bill.