load factor

A metric measuring the percentage of available seating capacity that an airline or transport provider has filled with passengers.

Load factor is a key operational metric in the transportation industry, most notably used by airlines and passenger rail operators. It measures the percentage of available seating capacity that a carrier successfully fills with passengers over a given period or route. By tracking this metric, companies can evaluate how efficiently they are utilizing their fleet and matching their transport supply with market demand. To calculate load factor, an operator divides its revenue passenger miles (RPMs)—the total miles flown or traveled by paying passengers—by its available seat miles (ASMs), which represent the total passenger-carrying capacity of the fleet. This calculation yields a percentage that reflects capacity utilization. For investors, load factor is a vital indicator of operational efficiency because transportation businesses carry high fixed costs, such as fuel, aircraft leases, and flight crew salaries. Spreading these fixed expenses across more paying passengers lowers the unit cost per passenger and boosts profitability. However, investors must analyze load factor alongside pricing metrics like yield (average fare paid per mile). A very high load factor achieved by aggressive ticket discounting can actually depress margins, while a lower load factor paired with premium pricing can sometimes generate superior financial returns.

Airline A operates a daily flight with 150 seats over a distance of 1,000 miles, resulting in 150,000 available seat miles (ASMs). If the airline sells tickets to 120 passengers for this flight, it generates 120,000 revenue passenger miles (RPMs). The load factor is calculated as 120,000 / 150,000 = 80%.