Boat Fuel Trip Cost Calculator
Calculate the fuel cost for your next boat trip. Enter your distance, speed and fuel price to estimate total litres needed and trip cost in Australian dollars.
How to Use
- Enter the one-way distance of your trip in nautical miles
- Enter your expected cruising speed in knots
- Enter fuel consumption per engine in litres per hour (check your engine manual or use our Engine Consumption calculator)
- Enter the current fuel price in dollars per litre
- Select number of engines and whether it's a round trip
- Adjust fuel reserve (10% is the recommended minimum)
Tip: If you don't know your fuel consumption in L/hr, a rough guide for petrol outboards is 0.4 L/hr per HP at full throttle and about 0.25 L/hr per HP at cruising speed (60-70% throttle).
Fuel reserve: The maritime rule of thirds recommends one-third of fuel for the trip out, one-third for the return, and one-third as reserve. Our default 10% reserve is the minimum — increase it for offshore or unfamiliar waters.
Frequently Asked Questions
How much does it cost to fuel a boat in Australia?
It depends on engine size, speed and distance. A typical 5m tinny with a 75 HP outboard cruising at 20 knots burns about 20 L/hr. At $2.10/L, a 2-hour round trip costs roughly $84 in fuel. Larger boats with twin engines can cost $200-500+ per trip.
How do I calculate fuel cost per nautical mile?
Divide your fuel consumption in litres per hour by your speed in knots to get L/NM, then multiply by the fuel price per litre. For example: 30 L/hr ÷ 20 knots = 1.5 L/NM × $2.10 = $3.15 per nautical mile.
How much fuel reserve should I carry on a boat?
The maritime rule of thirds is safest: one-third for going out, one-third for returning, one-third reserve. At minimum, carry 10% reserve. For offshore trips or unfamiliar waters, increase to 20-30% reserve.