Ever heard of Fitts's Law? No, it's not the latest social media trend. It's a simple principle about how quickly people can hit a target, and it shows up all over design.
Say you're walking through a busy city, trying to get to a specific spot. Would you take a narrow, cluttered alley or a wide, clear path? It's a no-brainer, right?
The law predicts that the time required to rapidly move to a target area is a function of the ratio between the distance to the target and the width of the target.
— Wikipedia, Fitts's Law
Fitts's Law is that wide, clear path in the digital world. It says that the time it takes to reach a target depends on the size of the target and how far away it is. In design, that means the bigger and closer a clickable area is, the easier and quicker it is for people to hit.
Take your mobile app's navigation bar. Larger icons or buttons placed closer to the thumb are easier to tap, so picking an option takes less effort.
For instance, think of Spotify. Or any other music player app. In practically all of them, the "Pause" button is big and sits within thumb reach at the bottom center of the screen.
A larger, closer target means quicker and more accurate taps. The same logic helps accessibility, especially on touch devices.
This matters most for icons, where the tappable area should be larger than the icon itself so people can actually hit it. Aesthetics matter, but so does making the path from point A to B an easy one.
Fitts's Law is a useful thing to keep in your back pocket. Applying it doesn't mean making everything bigger. It means sizing and placing the things people use most so they're easy to reach. So, future designer, make the important targets easy to hit.
Further reading
- Fitts's Law and Its Applications in UX on Interaction Design Foundation.
- Fitts' Law In The Touch Era on Smashing Magazine.
- Fitts's Law: The Importance of Size and Distance in UI Design on Nielsen Norman Group.
