Fuel conversion
Miles use 1 mi = 1.609344 km. Fuel used = kilometres × L/100 km ÷ 100, then the selected fuel price is converted to a price per litre.
Interactive Tool
Build a road trip budget
Add the costs you expect, switch units when needed, and see a transparent total for the whole trip and each traveller.
A planning estimate built from your inputs
Distance is converted to kilometres, fuel economy to L/100 km, and fuel price to a price per litre. Fuel cost = distance × L/100 km ÷ 100 × price per litre. Lodging = nights × nightly price; dining = days × daily budget × travellers.
This page runs locally and has no route, location, traffic, live fuel-price or exchange-rate data. Actual spending can differ because of detours, vehicle load, weather, taxes, changing prices, shared rooms, meal choices and unplanned costs.
US gallon and UK gallon
A US gallon is 3.785412 L; a UK Imperial gallon is 4.54609 L. US mpg uses 235.215 ÷ mpg, while UK mpg uses 282.481 ÷ mpg.
Budget total
Total budget = fuel + tolls + nights × nightly price + dining days × daily meal budget × travellers + other expenses. The per-person result divides that total by travellers.
Sources and conversion notes
The unit constants and fuel-economy context are based on these public NIST, EPA and DOE references:
- NIST Guide to the SI, Appendix B NIST provides the mile-to-kilometre conversion used by the planner.
- NIST Guide to the SI, Appendix B.9 NIST lists 1 US gallon = 3.785412 litres and 1 UK Imperial gallon = 4.54609 litres. A US gallon and a UK gallon are not interchangeable.
- US EPA Fuel Economy EPA explains official fuel-economy estimates and provides vehicle data for comparison; this planner uses the value you enter.
- DOE/EPA fueleconomy.gov The DOE/EPA site is a reference for published vehicle economy. This page does not look up a vehicle, route or current price.
Road trip budget questions
What does the total budget include?
It adds estimated fuel, tolls, accommodation, dining and other expenses. Accommodation is nights multiplied by the nightly price; dining is days multiplied by the per-person daily budget and the number of travellers.
Why do US mpg and UK mpg need different options?
US mpg measures miles per US gallon, while UK mpg measures miles per UK Imperial gallon. The gallons hold different volumes, so the same mpg number gives a different L/100 km result.
Does the planner use live prices or exchange rates?
No. It runs in your browser and uses only the values you enter. Currency selection formats the result; it does not convert a price or retrieve an exchange rate.
Can I use zero for tolls, nights or other costs?
Yes. Tolls, accommodation nights, nightly price, dining days, meal budget and other expenses accept zero when that cost does not apply. Distance, fuel economy, fuel price and travellers must be greater than zero.
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Verify the result before you rely on it
Check destination-specific rules and compare a related planner. Tool outputs are planning aids, not official permission or live route data.