In aircraft design and aviation, “specific fuel consumption” (SFC) is a measure of an aircraft engine’s efficiency in terms of fuel consumption. It quantifies the amount of fuel required by the engine to produce a certain amount of thrust or power over a specified period. SFC is typically expressed in units of mass of fuel per unit of thrust or power per unit of time.
  
- is the specific fuel consumption in terms of power (typically in kg/W·hr).
- Fuel Flow Rate (mass) is the rate at which fuel is consumed by the engine (usually in kilograms per hour).
- Power is the engine’s output power (usually in watts or kilowatts).