Universal Principles of Design, Revised and Updated

Fitts’ Law

The time required to move to a target is a function of the target size and distance to the target.

According to Fitts’ Law, the smaller and more distant a target, the longer it will take to move to a resting position over the target. In addition, the faster the required movement and the smaller the target, the greater the error rate due to a speed-accuracy tradeoff. Fitts’ Law has implications for the design of controls, control layouts, and any device that facilitates movement to a target.1

Fitts’ Law is applicable only for rapid, pointing movements, not for more continuous movements, such as writing or drawing. It has been used to predict efficiency of movement for assembly work performed under a microscope, as well as movement of ...