UX Laws Cheatsheet

The laws every designer should know by heart.

Jakob's Law

Users spend most of their time on other sites. Your site should work like the sites they already know.

Fitts's Law

The time to reach a target depends on its distance and size. Big, close buttons are faster — put primary actions where thumbs already are.

Hick's Law

More choices = slower decisions. Cut options, or group them — don't make users compare 12 plans at once.

Miller's Law

Working memory holds ~7 (±2) chunks. Break long numbers, forms, and menus into small groups.

Peak-End Rule

People judge an experience by its peak and its end — not the average. Design the finale, not just the flow.

Zeigarnik Effect

People remember uncompleted tasks better than completed ones. Progress bars and checklists exploit this — unfinished business pulls users back.

Doherty Threshold

Keep response times under 400ms and users stay in flow. Above it, attention drifts and productivity collapses.

Aesthetic-Usability Effect

Beautiful things are perceived as more usable. Visual polish isn't decoration — it buys forgiveness for minor flaws.