A mobility aid device including a seat arrangement upon which a user sits when the mobility aid device is in operation, a main unit that supports the seat arrangement and includes a linear actuator arrangement for raising and lowering the seat arrangement relative to the main unit, and a wheel arrangement that supports the main unit on a floor surface, wherein the mobility aid device is driven in operation from a motor arrangement included in at least one of the main unit and the wheel arrangement, wherein the mobility aid device is propelled forwards or backwards, and turned by the motor arrangement, wherein the wheel arrangement includes two wheels mounted at lateral sides of the main unit, wherein the two wheels are mutually independently driven in operation by the motor arrangement, the mobility aid device is self-balancing using the two wheels by employing a control module that controls an electrical signal that is applied to the motor arrangement, and the wheels are contained within an area that is less than 120% of a seating area of the seat arrangement, characterised in that a footrest arrangement is coupled to the seat arrangement via an interfacing arrangement arranged between the linear actuator arrangement and the seat arrangement, the interfacing arrangement having a planar surface for engaging onto the seat arrangement, wherein the planar surface is substantially parallel to a planar component of the footrest arrangement, wherein the footrest arrangement is raised and lowered by the linear actuator arrangement together with the seat arrangement, and wherein the footrest arrangement has the planar component for receiving feet of the user, wherein the footrest arrangement is arranged such that the planar component is maintained parallel to the floor when the mobility aid device is in operation, wherein a plurality of spacers are arranged between the planar surface of the interfacing arrangement and the seat arrangement, for permanently raising the seat arrangement with respect to the interfacing arrangement. the wheel arrangement includes two wheels mounted at lateral sides of the main unit, wherein the two wheels are mutually independently driven in operation by the motor arrangement, the mobility aid device is self-balancing using the two wheels by employing a control module that controls an electrical signal that is applied to the motor arrangement, and the wheels are contained within an area that is less than 120% of a seating area of the seat arrangement, characterised in that a footrest arrangement is coupled to the seat arrangement via an interfacing arrangement arranged between the linear actuator arrangement and the seat arrangement, the interfacing arrangement having a planar surface for engaging onto the seat arrangement, wherein the planar surface is substantially parallel to a planar component of the footrest arrangement, wherein the footrest arrangement is raised and lowered by the linear actuator arrangement together with the seat arrangement, and wherein the footrest arrangement has the planar component for receiving feet of the user, wherein the footrest arrangement is arranged such that the planar component is maintained parallel to the floor when the mobility aid device is in operation, wherein a plurality of spacers are arranged between the planar surface of the interfacing arrangement and the seat arrangement, for permanently raising the seat arrangement with respect to the interfacing arrangement. <EOS>