Design Law Series: Part 3 — Unlocking Fitts’s Law for Effortless Design

Speed Meets Simplicity

Imagine you’re in a crowded subway station, rushing to catch the next train. Amid the hustle, you need to buy a ticket from the vending machine. The screen is cluttered, buttons are tiny, and the pressure is on. You fumble, misclick, and the train doors close before you even have your ticket. Frustrating, isn’t it?

This everyday annoyance highlights a crucial aspect of design that often goes unnoticed: the ease with which we can interact with interfaces. Enter Fitts’s Law, a principle that has been quietly shaping our digital and physical worlds to make interactions seamless and intuitive.

What is Fitts’s Law?

Fitts’s Law is a predictive model of human movement, primarily used in human-computer interaction and ergonomics. Proposed by psychologist Paul Fitts in 1954, the law asserts that the time required to move to a target area (like a button on a screen) is a function of the ratio between the distance to the target and the size of the target. In simpler terms:

• The closer and larger a target, the faster it is to click or tap.
• The farther and smaller a target, the longer it takes to interact with.