Fuel Cost Calculator
Our fuel cost calculator shows your annual petrol, diesel, or EV running costs based on your annual mileage, fuel efficiency, and current UK fuel prices. Whether you are comparing vehicles, deciding whether to go electric, or simply budgeting accurately for transport costs, this calculator provides the full picture.
Fuel Cost & Car Running Cost Calculator
Calculate your annual fuel spend and total car running costs. Compare petrol vs diesel vs EV.
Current UK Fuel Prices 2026
In mid-2026, average pump prices are approximately 155–165p per litre for unleaded (E10) and 158–168p for diesel. A car covering 10,000 miles per year at 40mpg and 160p per litre costs approximately £1,820 in fuel alone. Electric vehicles cost significantly less per mile for energy. At domestic electricity rates of approximately 26p per kWh (Q3 2026 price cap) and a typical EV efficiency of 3.5 miles per kWh, the pence-per-mile cost is approximately 7.4p — compared with 18p for the petrol example above. Over 10,000 miles, the energy saving is approximately £1,060 per year. Use our Budget Planner to incorporate your total monthly transport cost alongside fuel, and our Income Tax Calculator to check whether claiming HMRC approved mileage allowance (45p per mile for first 10,000 business miles) is relevant to your situation.
Frequently Asked Questions
Fuel efficiency is measured in miles per gallon (mpg) for petrol and diesel, or miles per kWh for EVs. Official WLTP figures typically overstate real-world efficiency by 10–20% — use real-world figures from owner reviews for accurate cost modelling.
Yes — smooth acceleration, maintaining steady speeds, and reducing motorway speeds from 80mph to 70mph can improve real-world fuel efficiency by 10–20%. Under-inflated tyres increase fuel consumption by up to 3%.
Self-employed workers and employees using personal vehicles for business can claim HMRC approved mileage allowance: 45p per mile for the first 10,000 business miles and 25p thereafter, free of income tax and NI.
Calculate the fuel saving per year (current mpg vs new mpg × annual mileage × fuel price per litre) and compare against the additional purchase cost. High mileage drivers (15,000+ miles/year) see faster payback on more efficient vehicles.
Vehicle Excise Duty (VED) for zero-emission EVs was £195 per year from April 2025, rising to £620 from April 2026 for most EVs. Petrol and diesel cars pay rates based on CO2 emissions for the first year, then a standard rate of £195 per year.
Enter your vehicle’s fuel economy in miles per gallon (MPG). Use the real-world figure from your onboard trip computer over mixed driving rather than the WLTP official figure, which typically overstates economy by 10-20% for petrol and diesel vehicles. Hybrid vehicles show the greatest divergence — their official economy assumes optimal conditions. The fuel price field defaults to current average pump prices; adjust for your local forecourt. Annual mileage: total your commute miles, business miles, and leisure mileage. The result shows annual fuel cost and cost per mile, which is useful for comparing driving against public transport, for business mileage reimbursement planning, and for evaluating the running cost difference between vehicles at different economy ratings.
Important Information
This calculator is provided for general information and planning purposes only. It does not constitute financial or tax advice and should not be relied upon as such. Figures are indicative estimates based on simplified, publicly available criteria and stated assumptions. Actual results depend on your full circumstances. See our Disclaimer for further information.