Laws of UX

What is Laws of UX?

Laws of UX is a free reference website that catalogs fundamental principles and heuristics designers should apply when building user interfaces, created by Jon Yablonski. The site presents over 30 established laws, effects, and cognitive principles—ranging from foundational concepts like Fitts's Law and Hick's Law to modern additions such as the Paradox of the Active User, Selective Attention, and Cognitive Bias—each with concise definitions and explanations of how they influence user behavior and design decisions.

The collection draws from established fields including cognitive psychology, behavioral economics, and human-computer interaction research. Each principle is presented as a standalone entry defining the concept and its practical relevance to interface design. Examples include the Aesthetic-Usability Effect (users perceive aesthetically pleasing designs as more usable), the Doherty Threshold (productivity peaks when system response time remains under 400 milliseconds), and Miller's Law (average working memory capacity is 7±2 items). The site also covers organizational principles like the Law of Proximity and Law of Similarity from gestalt psychology, decision-making concepts such as Choice Overload and the Goal-Gradient Effect, and performance considerations including Tesler's Law on complexity conservation and Parkinson's Law on task inflation.

Yablonski maintains the resource as a living catalog, regularly adding new principles and updating existing entries. The site offers content in multiple languages including Spanish, French, Arabic, and Farsi, making it accessible to international design communities. Laws of UX functions as both an educational tool for design students and a practical reference for experienced practitioners. The site includes a downloadable large-format index poster featuring all laws, available for purchase, alongside free web-based access to the complete collection.

The resource serves product designers, UX researchers