Abstract: A seat lift employs an integral linkage which causes the seating surface to rise, move forward and tilt as the unit is actuated. The seat motion emulates the natural motion of a person rising from a seated position and is directed by combined linkages of different lengths. A hinged section of the front of the seat surface doubles as an integral linkage and provides a vertical component of motion when the seat is powered. The linkage mechanism is easily adapted to seat lifts of all kinds, such as wheelchairs and public seating in addition to furniture and a portable seat lift. When pneumatically powered, the system employs an easily replaced air chamber which has standardized mounting features and is a cylinder formed of flexible, non-elastic fabric. Separate, easily controlled means are provided to inflate and deflate the air chamber.