Enter the fuel consumption rate (grams per second) and the power produce by the engine (watts) into the calculator to determine the BSFC.

BSFC Formula

The following formula is used to calculate brake-specific fuel consumption. 

BSFC = r / P
  • Where BSFC is the brake-specific fuel consuption ( g/J)
  • r is the standard rate of fuel consumption (grams per second, g/s)
  • P is the power output by the engine (watts, W)

To calculate brake specific fuel consumption (BSFC), divide the standard rate of fuel consumption by the power output of the engine.

BSFC Definition

What is BSFC?

BSFC, which is short for break-specific fuel consumption, is a measure of the fuel efficiency of any engine that burns fuel in order to produce a rotational movement and power.

Example Problem

How to calculate BSFC?

  1. First, determine the rate of fuel consumption of the engine.

    In this example, the engine consumes a total of 2.75 grams of fuel per second.

  2. Next, determine the power output of the engine.

    This engine is able to output 40 watts of energy.

  3. Finally, calculate the BSFC.

    Using the formula, the break-specific fuel consumption is found to be:
    BSFC = r / P
    BSFC = 2.75/40
    BSFC = r / P
    BSFC = .06875 g/J