Functional unit

A functional unit refers to the product, service, or system whose impacts are calculated by a life-cycle assessment (LCA). Common examples of food-related functional units are 1 kg of beef, 100 calories of food, or 1 ha of land. The choice of functional unit influences an LCA’s results and care is needed when comparing the results of LCAs with different functional units. The functional unit is defined in the first phase of a life-cycle assessment study – that of goal and scope definition.