Road Trip Cost Calculator
Estimate fuel-only spend for an entered road trip distance, fuel economy and fuel price with explicit metric, UK or US gallon units.
How to use Road Trip Cost Calculator
1. Enter Distance, Distance Unit, Fuel Efficiency, Efficiency Unit, Fuel Price, Fuel Price Unit. 2. Use the whole road-trip distance on the chosen one-way or return basis. The fuel model excludes accommodation, tolls, parking, hire, maintenance and passenger splitting. UK and US gallons are distinct. Distance uses the international mile (1.609344 km); a UK gallon is 4.54609 L and a US liquid gallon is 3.785411784 L. Currency selection does not convert exchange rates. 3. Select Calculate or press Enter. 4. Select Copy result to copy the answer, or Reset to clear the form and result.
Why use this tool?
Compare entered road trip costs using the units and assumptions shown without fetching prices.
How the calculation works
Convert the entered distance and fuel economy to litres used, then multiply by fuel price per litre. L/100 km uses kilometres × consumption ÷ 100; km/L uses kilometres ÷ economy; mpg uses miles ÷ economy and the chosen gallon. Use the whole road-trip distance on the chosen one-way or return basis. The fuel model excludes accommodation, tolls, parking, hire, maintenance and passenger splitting. UK and US gallons are distinct. Distance uses the international mile (1.609344 km); a UK gallon is 4.54609 L and a US liquid gallon is 3.785411784 L. Currency selection does not convert exchange rates. Amounts use the selected currency’s standard minor units; halfway amounts round away from zero and nonzero subminor values are identified. Currency selection labels values without an exchange rate. Unit references: NIST Guide to the SI, Appendix B.8; NIST Handbook 44, Appendix C (US liquid-gallon cubic-inch definition).
Example
Worked example (GBP): Distance = 300; Distance Unit = "miles"; Fuel Efficiency = 30; Efficiency Unit = "mpg (US)"; Fuel Price = 4; Fuel Price Unit = "per US gallon". Result: £40.00.
Practical tip
Use total distance on the basis you intend to cost, a strictly positive fuel-efficiency value, and a price unit that matches the quoted price.
Frequently asked questions
Can I mix distance, fuel-efficiency and fuel-price units?
Yes. The calculator explicitly converts the selected kilometre/mile and litre/UK-gallon/US-gallon bases before calculating fuel cost. UK mpg and US mpg use different gallon definitions.
Are prices, exchange rates or charges fetched?
Use the whole road-trip distance on the chosen one-way or return basis. The fuel model excludes accommodation, tolls, parking, hire, maintenance and passenger splitting. Select one currency for all amounts; changing it labels the figures without applying an exchange rate.
How are currency results rounded?
Exact entered decimal arithmetic is applied before display rounding to the selected currency’s standard minor units. Halfway amounts round away from zero; nonzero subminor amounts are identified. Per-distance results are rounded average rates, not a reconciled payment schedule.