An encoder driven non-handed electric door operator for operating a door comprises an encoder, shaft, coil spring and a motor. The motor is configured to receive an external set of predetermined instructions. A plurality of gear assemblies in communication with each other allow the door operator to function. The shaft is solid and has nondetachable gear/splines at each end that drives the door operator. A controller which may be at a remote location transmits an external set of predetermined instructions to the encoder motor for proper operation. The door operator also has top and bottom plates that are parallel to each other. The plates are spaced a distance sufficient from each other to accommodate the encoder motor, encoder motor mounting plate, first, second and third gear assemblies, shaft, and coil spring therebetween.