Fuel Cost Calculator
Calculate the petrol or diesel cost of any journey using UK miles per gallon.
Your result
Updates as you type. Based on 2025/26 UK figures where relevant.
How this is worked out
Divide miles by MPG to get gallons, convert to litres (1 UK gallon = 4.546 litres), then multiply by the price per litre.
Tips
- UK MPG uses imperial gallons (4.546 litres), which differ from US gallons.
- HMRC's approved mileage rate is 45p per mile for the first 10,000 business miles.
- Home EV charging on an off-peak tariff is usually far cheaper than public rapid chargers.
Guides for this calculator
- How to Calculate Fuel Costs for a Journey in the UK: Step-by-Step Guide
- Fuel Costs for a Journey: Common Mistakes, Tips and FAQs
More motoring calculators
Frequently asked questions
How does the fuel Cost Calculator work?
Divide miles by MPG to get gallons, convert to litres (1 UK gallon = 4.546 litres), then multiply by the price per litre.
What MPG should I use?
Use your real-world figure from your car's trip computer if you can; official figures are often optimistic.
Can I claim for commuting miles?
No. Normal commuting to a permanent workplace doesn't count as business mileage.
How often do HMRC mileage rates change?
Rarely. The 45p rate has been unchanged for many years, but always check GOV.UK.
This calculator gives an estimate for general information. It isn't financial, tax, legal or medical advice. Check official figures on GOV.UK or NHS.uk, or speak to a qualified adviser.