BEHIND THE NUMBERS
How this calculation works
For UK mpg: litres = total miles ÷ mpg × 4.54609. For l/100 km: litres = total km × consumption ÷ 100. Fuel cost = litres × pence per litre ÷ 100. Add whole-journey extras, then divide by the people sharing.
Worked example
100 miles at 40 UK mpg uses 2.5 imperial gallons, or 11.365225 litres. Fuel is £17.0478375; with £10 extras the total rounds to £27.05.
Example result: £27.05
Use real-world consumption
A recent measured mpg figure is usually more useful for budgeting than an optimistic test figure. The result changes directly with fuel used.
Share the whole journey fairly
Enter all parking and tolls once for the journey selected. Equal shares are displayed to the penny; splitting a rounded total may leave a penny to allocate.
Assumptions and rounding
- A mile is 1.609344 km; an imperial gallon is 4.54609 litres.
- Return doubles distance, not the extras entered.
Questions about this calculator
Can I enter US mpg?
No. Convert it first or use litres per 100 km; a US gallon is smaller.
Are pump prices updated automatically?
No. Enter the price you expect to pay in pence per litre.