A shaft key is a mechanical element seated in matching keyways to transmit torque between a shaft and a hub, gear, pulley, or coupling. Torque creates tangential force, key shear stress, and bearing or crushing stress governed by shaft diameter, key width, height, length, and allowable stresses.
Shaft Key Calculator applies this concept to its defined inputs and workflow. It can be used as a browser-local shaft key calculator to review simple rectangular key torque transfer before detailed shaft design, fatigue, hub, fit, keyway, and standards review.
The calculator evaluates key shear stress, key bearing stress, required key length, and torque transfer and returns tangential force, shear stress, bearing stress, and required length using the stated method. The selected units and sign or reference conventions must describe one consistent physical case. Users should interpret the output within the assumptions shown on the page and repeat the check with trusted reference values when the result affects engineering or research decisions. No fatigue, shock, keyway stress concentration, fit, hub strength, spline, Woodruff key, retaining-ring, or material-certification check is included.