What is Fitts’ law? UI examples and best practices

Fitts’ law, established by psychologist Paul Fitts in 1954, is a key principle in human-computer interaction that explains the relationship between the time required to reach a target and its distance and size. This law is crucial in UX/UI design, as it suggests that larger and closer targets are easier and faster to interact with, thereby reducing user error and effort. It emphasizes designing interfaces with distinct, clickable, and well-spaced elements, considering the prime pixel and magic pixels for optimal placement. The law also highlights the importance of balancing whitespace and content to avoid clutter and ensuring that important actions are accessible, especially on mobile devices where touch targets need to be larger for finger interaction. However, it cautions against using Fitts’ law in scenarios like pop-up ads and cluttered interfaces, where it might lead to user frustration or unwanted actions. Despite its origins in the 1950s, Fitts’ law remains a fundamental guideline in creating intuitive and efficient user experiences, although it should be combined with usability testing to ensure designs are user-centered.