Overview
Load Factor is the ratio of the lift being produced by the wings compared to the weight of the aircraft. It is measured in Gs (acceleration of gravity). For example, a load factor of 2 Gs means that the total load — in effect, stress — being placed on the aircraft is twice the aircraft's weight. For Normal category aircraft (most light aircraft), the limit load factor is 4.4 Gs. This means that the aircraft is certified to withstand up to 4.4 Gs without fear of structural failure. Limit load factor is closely tied to the determination of design maneuvering speed (VA).
Rules of Thumb
Load Factor = Lift / Weight (expressed in number of "Gs")