Work out the fuel cost of a UK trip
Enter miles, your car’s MPG and the pump price. Useful when you want the actual fuel spend, not the flat HMRC mileage rate.
Why people run both numbers
The approved mileage rate is a flat figure that covers fuel, wear and tear and running costs. Your actual fuel bill for the same miles is often lower. Comparing the two helps you see what the rate is covering beyond the pump.
Company car drivers should use advisory fuel rates when reclaiming fuel from their employer, not this trip calculator and not the 55p approved rate.
Related: simplified expenses vs actual costs for the self-employed, and the mileage log template.
Quick answers
Is this the same as the HMRC mileage rate?
No. This estimates pump spend. The approved mileage rate for your own car is a flat figure (55p first 10,000 miles in 2026/27) that covers more than fuel.
UK gallon or US gallon?
Use UK (imperial) gallons. One UK gallon is about 4.546 litres. The calculator converts with that figure.