Mileage Calculator UK
Calculate your vehicle mileage (km per litre) from distance covered and fuel used.
How it works
A discount reduces the original price by a percentage. The saving is the price times the discount; the sale price is what remains.
Sale price = Price × (1 − discount%)Frequently asked questions
How do I calculate miles per gallon?
Divide miles driven by gallons used. In the UK, convert litres to gallons by dividing by 4.546 first.
What is the HMRC mileage rate?
For cars, 45p per mile for the first 10,000 business miles in the tax year, then 25p per mile, paid tax-free.
How do I measure my real mpg?
Note your mileage, fill up, drive a full tank, refill and record the litres, convert to gallons, then divide miles by gallons.
How many litres are in a UK gallon?
About 4.546 litres in an imperial gallon, which is what UK mpg figures are based on.
Is the HMRC rate the same for everyone?
The 45p/25p car rates are standard approved rates; employers may pay less (you can claim tax relief on the difference) but extra above them is taxable.
Why is my mpg lower than advertised?
Real-world driving — town traffic, loads, weather and driving style — usually returns lower mpg than the official test figure.
Calculating mileage and fuel economy
Mileage usually means fuel economy — how far your car travels per gallon — expressed in miles per gallon (mpg). It is calculated as miles driven ÷ gallons used. In the UK, where fuel is sold in litres, you convert litres to gallons by dividing by 4.546.
Working out mpg
Note your mileage, fill up and record the litres added over a tank. If you drove 360 miles and used 36 litres (about 7.92 gallons), your economy is 360 ÷ 7.92 ≈ 45 mpg. Measuring over a full tank is more reliable than a single short trip.
HMRC mileage allowance
For business driving in your own car, HMRC’s Approved Mileage Allowance Payments let employers reimburse 45p per mile for the first 10,000 business miles in a tax year, then 25p per mile above that, tax-free. Multiply your business miles by the relevant rate.
Tracking mileage helps you monitor efficiency, compare cars, budget for trips and keep accurate records for any business mileage claims.
Results are estimates for general guidance in United Kingdom and may not reflect the latest local rates, fees or rules. Check official sources before making decisions.