A useful budget is a set of visible assumptions. Distance, vehicle consumption, overnight style and the number of people explain far more than a single headline figure.
1. Calculate fuel
For a 1,200 km journey in a vehicle using 8 L/100 km at an assumed $2.00 per litre, the calculation is 12 × 8 × $2.00 = $192. Add distance for local driving and detours. Replace the assumed price with current route prices from FuelCheck.
2. Separate fixed and per-person costs
Route, vehicle and payment arrangement
Parking, cleaning and weekend surcharges
Self-catering versus restaurant plan
Entry, hire, tours and park fees
3. Add the forgotten line
Parking, tolls, ice, laundry, coffee, booking fees and a replacement cable rarely appear in the first estimate. Add a contingency instead of pretending they will not happen. The right margin depends on remoteness, vehicle age and how tightly the trip is booked.
4. Compare the correct alternatives
A one-way hire may cost more but save a return day and another hotel night. Camping reduces accommodation cost only after equipment, booking fees and extra fuel are counted. A longer route may still be the better-value holiday if the drive itself is the experience.
Worked planning example
Two travellers taking a five-night trip might enter 1,200 km, their actual fuel consumption, five accommodation nights, six food days and a separate extras amount. The total is then a decision tool—not a promise. Change the accommodation assumption first; it often moves the total more than small differences in fuel price.