Fitts's Law
Fitts’s Law describes the relationship between the distance to a target and the size of that target, stating that the closer and larger a target is, the faster it can be selected. In UX, this means that interactive elements (buttons, links, etc.) should be appropriately sized and placed for quick, efficient interactions.
🧠
The Psychology Behind It
Developed by Paul Fitts in 1954, Fitts’s Law suggests that our brain calculates the time it takes to move to a target based on two factors:
Distance: How far the user must move the cursor (or finger) to reach the target.
Size: How large the target is, which affects precision.
The law shows that smaller, distant targets are harder and slower to reach, while larger, closer targets are quicker to hit. This principle applies directly to the design of clickable UI elements.
📱
Real-World Applications
Mobile App Buttons: Larger buttons, especially at the bottom of the screen, are easier for users to tap (think of the “call” button on most phone apps).
Navigation Menus: Placing primary navigation options close to the edge of the screen reduces effort.
Form Fields: Large, easily clickable input fields improve form completion time.
Modal Windows: By placing close, prominent “close” buttons, users can quickly dismiss popups.
Visual Examples
Don’t
Continue
Do
Continue
🤦
Common Mistakes
Mistake: Using small, hard-to-target buttons, especially on mobile device
Fix: Make interactive elements larger, especially on mobile, and place them where users can easily reach them (e.g., thumbs near the bottom of the screen).
✏️
How to Apply It in Your Design
Make buttons large enough for easy interaction, especially on mobile devices.
Place important actions close to the user’s focus (like in the center or near the natural starting point).
Ensure adequate spacing between clickable elements to reduce accidental taps or clicks.
Consider ergonomic factors – for mobile apps, make sure key buttons are within the “thumb zone.”
✓
Key Takeaways
Closer and larger targets are quicker and easier to select.
Buttons, links, and input fields should be appropriately sized and placed.
In mobile design, consider thumb reach to ensure ease of interaction.
User Psychology 3
Psychology Behind UX Design
2025 Sigma. All rights reserved. Created with hope, love and fury by Ameer Omidvar.