Boat Fuel Efficiency Calculator

GPH and range from engine specs and speed.

Engine horsepower (HP)

Number of engines

Fuel type (0=gasoline, 1=diesel)

Engine load (%)

Fuel tank capacity (gal)

Cruising speed (knots)

Fuel price ($/gal)

Tab to move between fields

Fuel burn (GPH)

16.25

Nautical miles per gallon1.54

Statute miles per gallon1.77

Cruising range (NM)138.5

Cruising time (hours)5.5

Fuel cost per hour$89.38

Fuel cost per NM$3.58

How to Use This Calculator

Enter Engine horsepower (HP), Number of engines, and Fuel type (0=gasoline, 1=diesel).
Set Engine load (%), Fuel tank capacity (gal), and Cruising speed (knots).
Adjust Fuel price ($/gal) as needed.
Review the Fuel burn (GPH) result.
Use Nautical miles per gallon and Statute miles per gallon to inform your decision.

How the result changes with Engine horsepower (HP)

Engine horsepower (HP): Rated horsepower per engine.
Number of engines: Total engines powering the boat.
Fuel type (0=gasoline, 1=diesel): Gasoline engines burn ~0.10 gal/HP/hr; diesels ~0.055 gal/HP/hr.
Engine load (%): Average throttle/load percentage. Cruising is typically 60-70%.
Fuel tank capacity (gal): Total fuel tank capacity in gallons.
Cruising speed (knots): Speed over water at the given engine load.
Fuel price ($/gal): Current price per gallon of marine fuel.

Fuel burn (GPH): Gallons per hour consumed at the specified load.
Nautical miles per gallon: Distance in nautical miles per gallon of fuel.
Statute miles per gallon: Distance in statute miles per gallon of fuel.
Cruising range (NM): Range in nautical miles using 90% of tank (10% reserve).
Cruising time (hours): Hours of cruising before hitting fuel reserve.
Fuel cost per hour: Dollar cost of fuel per hour of operation.
Fuel cost per NM: Dollar cost of fuel per nautical mile traveled.

Identify Input Parameters
4 parameters
Engine horsepower (HP) = 250, Number of engines = 1, Fuel type (0=gasoline, 1=diesel) = 0, Engine load (%) = 65 = 7 input(s) provided
Calculate Fuel burn
Fuel burn = totalHP * loadFraction * sfc
16.25 = 16.25
Calculate Nautical miles per gallon
1.54 = 1.54
Calculate Statute miles per gallon
Statute miles per gallon = nmpg * 1.15078
1.77 = 1.77