Cost guide

Car fuel cost: how the annual figure is worked out

A car's annual fuel cost is the fuel it uses over your yearly mileage multiplied by the price you pay. For petrol and diesel cars, 73 Auto uses the car's official combined fuel consumption where one exists, adjusts it for your driving style, and prices it at the latest UK average pump price from the government's weekly road fuel price statistics. For electric cars it uses energy per 100 km and a price per kWh, which you can set to your own tariff.

Check what a specific car really costs to own

Published 2026-09-28 · Publisher: 73 Auto

How to work out fuel cost

litres a year = miles ÷ mpg × 4.54609 · annual fuel cost = litres × price per litre

UK mpg uses the imperial gallon, which is 4.54609 litres. As an illustration, a car that does 45 mpg driven 7,400 miles a year uses about 748 litres, which at 140p a litre is about £1,047 a year. Those inputs are an example, not today's price or a particular car.

Estimate a car's fuel cost

Enter a UK registration and your mileage for that car's fuel or charging cost at current UK prices. Your first check is free and shows the vehicle summary and its headline ownership cost. The category-by-category breakdown is part of a paid check.

UK number plate or 17-character VIN

Where the consumption figure comes from

73 Auto takes the most specific figure available for the car, in this order:

Your own real-world figure, if you enter one.
The official combined figure for the exact version of the car.
The official combined figure for the same model, year, engine and fuel.
A figure derived from the car’s official CO2 emissions (conventional petrol and diesel cars only).
Only as a last resort, a typical figure for the engine size, clearly labelled as low confidence.

The report says which of these was used. Driving style then adjusts it: calm driving improves economy by about 10%, aggressive driving worsens it by about 15%.

Where the price comes from

Petrol and diesel are priced from the UK government's weekly road fuel prices (Department for Energy Security and Net Zero), the national average pump price for unleaded petrol and diesel. Every calculation records which week's price it used. If you enter your own price per litre, that is used instead.

Hybrids and electric cars

DVLA records don't say whether a hybrid is self-charging or plug-in, so 73 Auto assumes a hybrid covers 60% of its miles on fuel and 40% on electricity and costs each part separately. For fully electric cars, the cost is miles × kWh per 100 km × price per kWh; the electric car running cost calculator shows the formula worked through.

What the fuel figure is based on

What the fuel figure is based on
Input	Where it comes from	Type
Fuel type, engine size, CO2 emissions	DVLA vehicle record	Official data
Official combined consumption	Official figure for the car or model, where one is available	Official data
Pump price	GOV.UK weekly road fuel prices (Department for Energy Security and Net Zero)	Official data
Electricity price	Your own tariff, or a default of 30p per kWh	Your input
Annual mileage and driving style	What you enter, or standard UK assumptions	Your input
Consumption when no official figure exists	Derived from CO2, or a typical figure for the engine size	73 Auto estimate

Full detail on every source is on the data sources page, and how each category is calculated is on the methodology page.

See fuel in a full worked example

A mid-priced worked example of each fuel type. Each page shows the fuel line alongside every other cost.

See fuel in a full worked example
Vehicle	Fuel	Per year	Per month	Per mile
MINI Mini 2018	Petrol	£5,078	£423	£0.69
Tesla Model Y Long Range AWD 2022	Electricity	£5,177	£431	£0.70
Toyota RAV4 2017	Diesel	£5,691	£474	£0.77
Toyota Corolla 2019	Hybrid Electric	£5,983	£499	£0.81

About these examples. All 53 were calculated under one standard scenario: 7,400 miles a year, 3-year ownership, finance purchase. They describe the specific vehicles 73 Auto has analysed, not every car of that type in the UK. They were calculated on 21 Jul 2026. Since then, 73 Auto has rebuilt its fuel prices and VED rules, tyres, servicing, repairs and maintenance, depreciation and insurance models, so a new report for the same car today can give different figures from its example.

Limitations

Official consumption figures are measured in standard tests and real-world economy is often worse, especially on short trips and in cold weather. Pump prices change weekly and vary by area. Enter your own economy and price for the closest figure.

How 73 Auto works this out

Every category is explained in the methodology, and the data sources page lists which inputs are official data and which are 73 Auto estimates. How pages are written and kept up to date is set out in the editorial policy; to report a factual error, see corrections.