Abstract: A floating modular stair system includes a wall mounting plate that is attachable to a vertical wall, and a base mounting plate that is anchorable to a horizontal floor. A monostringer beam is attachable to the wall mounting plate and to the base mounting plate. The monostringer beam includes an integrated hook attachment for variable angle adjustment and attachment to the wall mounting plate. Stair tread brackets are attachable to the monostringer beam for equal spacing of stair treads after installation of the monostringer beam to the wall mounting plate and to the base mounting plate. Each of the stair tread brackets are also designed for individual variable angle adjustment and leveling after attachment to the monostringer beam, and the stair tread brackets are rotatable through an adjustable anchor point about a fixed pivot anchor point to level the stair treads of the floating modular stair system.