Enter the specific fuel consumption, horsepower, and fuel-specific weight into the calculator to determine the boat fuel consumption.

Boat Fuel Consumption Formula

The following formula is used to calculate a boat’s fuel consumption.

FC = (SFC * HP) / FSW
  • Where FC is the fuel consumption at max throttle (gallons/hour)
  • SFC is the specific fuel consumption (lbs per HP)
    • Gas = .50 lbs per HP
    • Diesel = .40 lbs per HP
  • HP is the engine horsepower
  • FSW is the fuel specific weight (lbs per gal)
    • Gas = 6.1 lbs per gal
    • Diesel = 7.2 lbs per gal

To calculate boat fuel consumption, multiply the fuel consumption at max throttle by the engine horsepower, then divide by the fuel specific weight.

What is a boat fuel consumption?

A boat fuel consumption is a rate at which the engine on a boat consumes fuel, typically measured in gallons per hour.

The fuel consumption depends on the horsepower of the engine, throttle level, and type of fuel used.

How to calculate boat fuel consumption?

Example Problem:

The following example outlines how to calculate the fuel consumed by a boat engine.

First, determine the horsepower of the engine. In this example, the boat has one engine with a horsepower of 400 HP.

Next, determine the specific fuel consumption and fuel-specific weight of the fuel. In this example, the fuel is gas so these values are .50 and 6.1 respectively.

Finally, calculate the fuel consumption at max throttle using the formal above:

FC = (SFC * HP) / FSW

FC = (.50 * 400) / 6.1

FC = 32.786 gallons per hour

To determine how much fuel would be used at half throttle/half horsepower, divide the result by 2.

32.786 / 2 = 16.393 gallons per hour