Boat Fuel Range Calculator
Determine safe operating cruising range, fuel economy, and endurance applying the Rule of Thirds.
Recommended Tools & Equipment
Tested hardware and components for high reliability
How Offshore Fuel Planning Works
Running out of fuel on the water is among the leading causes of US Coast Guard search-and-rescue dispatches. Unlike cars, boats encounter adverse currents, heavy chop, and trim tab drag that can increase fuel consumption by 30% to 50%.
Fuel Economy (NMPG) = Speed (Knots) / Burn Rate (GPH)
Usable Fuel = Total Capacity × (1 - Reserve %)
Safe Range = Usable Fuel × Fuel Economy
Frequently Asked Questions
What is a good fuel economy for an outboard boat?
A typical 20-25 ft center console averages 2.0 to 3.0 MPG at cruising speed. Heavy offshore twin-engine boats typically achieve 1.2 to 1.8 NMPG.
Why should I never rely on the last 10% of tank capacity?
Boat fuel pickups sit slightly above tank bottoms to avoid drawing water and sediment. In rough seas or while on plane with bow-high attitude, fuel sloshes away from the pickup tube, causing engine stalling.
How does marine diesel compare to gas consumption?
Diesel fuel contains roughly 139,000 BTU per gallon versus 114,000 BTU for gasoline, yielding approximately 25% to 35% better fuel economy per gallon at comparable horsepower.