The laws of UX: 28 simple rules for better design

When designing anything digital — whether websites or apps — one thing is certain:  the user comes first. This is what’s known as ‘user-centric design’, and it matters. A lot. 

Why? Because if your design doesn’t make sense or it’s a pain to use, people will leave faster than you can say “hello”. And this means no engagement, no sales, and ultimately, no business. Luckily, there are techniques to help you see the world from their perspective and create products that click (no pun intended). 

The laws of UX are simple, tried-and-tested psychological principles that help digital designers anticipate how users interact with a website or app. This makes it easier to create intuitive experiences, which in turn increases the odds of users staying. 

What are the laws of UX, and why do they matter?

The laws of UX are based on how people think and behave when they interact with technology. 

These principles take their bearings from various fields, including psychology, cognitive science, and design theory. By understanding them and applying them to UX, designers can create smoother, more intuitive experiences that work as people expect. 

Predictability may sound boring, but when it comes to functionality, it’s a good thing. It helps users accomplish their goals with less fiction, which means you can accomplish yours — whether that’s a sale, a sign-up, or both.

The laws of UX fall into three main categories (plus a bonus ‘misc’ section): Heuristics, Gestalt principles, cognitive bias, and additional principles.

In the next section, we’ll take a closer look at what each of these means via 21 of the top laws of UX. 

The 21 laws of UX

Ready to create designs users love? Here are the 21 principles to help you on your way. 

Heuristics

Heuristics are mental shortcuts that people use to make speedy, often unconscious decisions. Knowing how to apply them means you can create websites and apps that work with users’ natural inclinations, guiding them toward their (and your) goals. 

1. Working memory

Working memory is the part of your brain where you temporarily store information just long enough to complete a task.  For example, remembering a phone number long enough to dial it. Working memory is limited — it can only hold so much at once. 

In UX, this means you should design interfaces that don’t mentally overburden the user. Break tasks into smaller steps. A user-friendly form, for example, should only display the fields the user needs at the moment rather than overwhelming them. 

2. Miller’s law

So when it comes to respecting working memory, how much is too much? 

In 1956, cognitive psychologist George A. Miller discovered people can only hold about seven pieces of information in their short-term memory at once. This “magic number” often ranges between 5 and 9 items, depending on the complexity of the information. 

In UX, this means you should avoid overloading users with too much data at one time. Break information into chunks. Use categories, tabs, or progressive disclosure (showing only what’s needed at a given moment).

By respecting users’ mental limits, you make it easier for them to process and ultimately act on the information you present.

3. Chunking

Chunking is the brain’s way of organizing information into smaller, more manageable groups. 

In design, it gives users a helping hand when it comes to processing data. For example, in a phone number field, grouping digits into sets of three or four makes the number easier to read and remember. This lowers cognitive strain and speeds up tasks.

To use this principle, organize information into logical groupings that users can digest quickly. Whether it’s a form, a menu, or a list, break down data into bite-sized bits. 

4. Aesthetic-usability effect

This law says that people are more forgiving of problems if something looks good. 

Just like a well-dressed person exudes competence, a slick website makes users think it works better (even if it doesn’t). This doesn’t mean style is more important than function — after all, looks only get you so far. It means good design builds trust and helps users feel reassured. For example, a fancy-looking website might have a slow-loading page due to videos, but users are more likely to wait if they enjoy what they see.

To use this in your design, aim for clean layouts and imagery that matches the tone of your product. But remember — it’s a finely tuned dance between site speed and aesthetics, where the sweet spot depends on the industry you’re in. This is especially true for lifestyle or creative brands, which tend to need site-slowing imagery and videos while keeping things user-friendly.

5. Hick’s law

Hick’s law, named after psychologists William Edmund Hick and Ray Hyman, describes how decision-making time increases with complexity. This is because the brain takes longer to process more options and weigh decisions.

For example, a crowded navigation menu with 20 items slows users down compared to a simpler one with just 5 core options. Overwhelmed users might freeze and abandon the task altogether — aka analysis paralysis — if they can’t decide.

To apply Hick’s law, limit the choices you show at once. Use techniques like chunking to group similar items together, collapsing less important details into menus, and giving clear signposts. 

6. Flow

Flow is a mental frame of mind. It’s a state of perfect engagement, where everything feels effortless, and time slips away. 

In UX, the goal is to create designs that help users enter a flow state. When users can perform tasks with minimal effort and maximum focus, they experience satisfaction. Think about a game that gradually increases in difficulty to keep you engaged without overwhelming you — this balance helps you stay in the zone.

To create flow, keep tasks challenging but not frustrating. Show clear progress indicators, and remove unnecessary interruptions. Make sure the design feels intuitive, so users can navigate without effort for a smooth experience. 

7. Fitts’s law

Fitts’s law is all about speed and accuracy. It says that the time it takes to click or tap on something depends on its size and distance. Bigger and closer targets are easier to hit, while smaller and farther ones slow people down.

Think about a button on a mobile app. If it’s too small or far from where users’ thumbs naturally rest, they’ll struggle to tap it. Not ideal. 

To use this law for better designs, make important buttons big and easy to see. On mobile apps, place clickable things in thumb-friendly zones, and for desktop, make sure buttons are large and spaced well. This improves speed and keeps frustration to a minimum. 

8. Goal-gradient effect

The goal-gradient effect is rooted in psychology. It says people work harder or stay more focused when they feel they’re nearing a goal. This principle comes from behavioral studies where animals and humans alike showed increased motivation as they got closer to completing a task.

In UX, this is why progress bars or task trackers work so well. For instance, when filling out a profile, showing a bar that says “80% complete” encourages users to finish because the end feels achievable. Whether it’s checkout processes, onboarding flows, or learning modules, giving users a sense of progress keeps them engaged.

9. Parkinson’s law

Parkinson’s law says that “work expands to fill the time available for its completion”, or in other words, a 10-minute job will take 60 minutes if you’re given that long to complete it. Feel familiar? 

In UX, this means tasks without clear time limits or structure tend to drag on. For example, a long signup process without any progress bar feels endless. But when users know it’ll “only take 2 minutes,” they’re more likely to stick with it.

Parkinson’s Law is a close cousin of the goal-gradient effect mentioned above. Both underscore the importance of creating boundaries. Add time estimates, progress bars, or gentle nudges like “Just one step left!” These give users a sense of control and urgency, helping them finish faster. 

10. Jakob’s law

Jakob’s law (named after UX expert Jakob Nielsen, a web usability expert) is all about user expectations. He realized that people spend most of their time on other websites or apps, so they bring those experiences to yours. If your design feels familiar, they’ll pick it up quickly. If it’s too different, they’ll get confused.

Think about how most shopping sites place the cart icon in the top-right corner. If you moved it to a random spot, users might struggle to find it because it breaks their mental model.

To follow Jakob’s law, use familiar design patterns and common layouts. Don’t try to reinvent the wheel unless it’s truly better. Familiarity makes your site or app feel intuitive and easy to use.

11. Mental model

This one is essentially Jakob’s Law by another name. When users come to your interface, they bring their expectations — formed by past interactions with similar products — and try to apply those expectations to your design.

For example, users expect a shopping cart to be represented by a cart icon. If you use something that doesn’t fit their mental model, like a rocket ship, they might be confused.

Stay consistent with common conventions so users can navigate your design easily without having to learn everything from scratch. 

Gestalt principles

Next up: Gestalt principles. These are like magic tricks for the brain. They explain how we naturally group and organize what we see. 

Our brains love patterns — they want to turn chaos into order, often in ways we don’t even realize. These principles include proximity (grouping related items together) and similarity (using similar elements to show they belong together). By applying these ideas, designers can create layouts that feel more intuitive.

12. Law of common region

Imagine a picnic blanket at a park. If you see a group of people sitting together on the same blanket, you assume they’re part of the same group — even if they’re not close to each other.

In design, this means elements inside the same boundary (like a box or a colored background) appear related. For example, on a login page, grouping “Email” and “Password” fields inside a single box signals to users: “These belong together.” This helps users navigate better while lowering the cognitive load. 

To use this, draw visual boundaries around related elements using boxes, shapes, or backgrounds. This keeps things tidy and helps users understand your layout.

13. Law of proximity

The law of proximity is the buddy system of design. Closely related to the law of common region, it dictates that things that are close together are assumed to belong together — like two people standing shoulder-to-shoulder in a crowd.

For example, when you see a label right above a form field, you know they’re connected. But if the label is far away, you might get confused about which field it belongs to.

To use this, place related items close to each other and keep unrelated ones apart. On a pricing table, for instance, put the price right under the plan name so users can connect the dots.

14. Law of similarity

Humans naturally group things that look alike — like aisles of similar products in a supermarket. 

In UX, users assume that similar-looking elements are related. For example, a navigation bar with buttons that share the same color and size feels cohesive. But if one button looks different, it stands out and signals it might do something special.

To use this, keep related items visually consistent. But if you want something to grab attention — like a “Sign Up” button — make it stand out with a bold color or style.

15. Law of prägnanz

The law of prägnanz also called the law of simplicity, is about how our brains are like lazy artists. They’ll always pick the simplest way to understand what they’re looking at. If they see a complicated shape, they’ll break it into easier pieces to make sense of it.

Imagine looking at a pile of laundry on a chair. Instead of focusing on every crumpled shirt and sock, your brain simplifies it into one concept: “a pile of clothes.” This mental shortcut keeps things manageable. To use a design-related example — think of the Olympic rings. Your brain sees five circles, not what they really are — a collection of overlapping curved lines.

In design, this means keeping things clean and simple. Reduce clutter, use clear shapes, and let your visuals “breathe.” When users don’t have to work hard to understand your design, they’ll feel more at ease.

16. Law of uniform connectedness

The law of uniform connectedness is like connecting the dots. When two things are linked by a line or shape, our brains see them as part of the same story, even if they’re far apart.

Imagine a subway map. The stations might be spaced out, but the connecting line tells you they’re on the same route.

In UX, you can use this to clarify relationships. For instance, connect form fields with lines or use arrows to guide users in tutorials. It’s a simple way to reduce confusion and help users understand how things fit together.

Cognitive bias

Cognitive biases are unconscious patterns of thought that affect how we make decisions. We often think of them as bad things, especially in the workplace — but in the world of UX, understanding these quirks helps you predict how users might process information and respond to certain design elements. 

17. Selective attention

Selective attention is the brain’s ability to focus on certain information while blocking other things. For example, taking in a conversation in a busy restaurant or finding Waldo in a sea of decoys. Our brains filter out irrelevant information relatively well. 

In design, selective attention can help direct users’ focus to the most important elements with a little help from the design team. For example, a call-to-action button should stand out visually from the background so users naturally focus on it and take action.

18. Peak-end rule

The peak-end rule is like remembering a vacation. You might forget most of the trip, but you’ll always recall the best part (a sunset at the beach) and the end (the stress of losing your luggage). This rule says people judge an experience based on its most intense moment (the “peak”) and the way it ends rather than the entire experience.

In UX, this means users will remember a standout moment (good or bad) and how your app or website made them feel at the end. A seamless checkout process that ends with a cheerful confirmation message can leave a lasting positive impression, even if there is a small moment of frustration along the way.

To apply this, create moments that delight users. Add animations, success messages, or even small surprises. And always end on a high note—make sure confirmation pages, thank-you messages, or the final interaction feel rewarding.

19. Serial position effect

Ever wondered why you choose dishes at the top or bottom of the menu but not the middle? The serial position effect explains why you’re more likely to remember the first and last items in a list but forget everything in between. It’s rooted in how short-term memory works: the brain focuses on beginnings (primacy effect) and ends (recency effect). But the stuff in the middle? That’s harder to recall.

Restaurateurs use this when designing menus, putting quick-to-cook, high-value items at the start and end of the list of dishes. You remember the first item because it stands out and the last because it’s fresh in your mind. What the owner wants to sell more of will go in either spot. 

In UX, this means you should put key actions or important information at the start or end of menus, lists, or flows. For example, in a navigation bar, place critical links like “Home” or “Contact” at the edges where they’re easier to spot.

20. Paradox of the active user

The paradox of the active user is the idea that users want to have control over their actions but don’t want to feel overwhelmed by too many choices. In other words, they want to make decisions, but they also want a little helping hand.

It’s a bit like trying to choose a movie on Netflix. You don’t want the app to make a choice for you, but you also don’t want it to spit out hundreds of options without any personalized filtering.

It’s the same in UX: the key is to strike a balance. Give users the freedom to make decisions, but offer enough structure to help them make informed choices without being overwhelmed.

21. Von Restorff effect

The Von Restorff effect says people remember things that stand out from the crowd. If something looks different, it grabs attention and sticks in your memory.

In UX, this means you can make a feature, button, or message more noticeable by giving it a unique color, size, or style. For example, a red “Delete” button stands out on a screen full of blue action buttons, warning users to think twice before clicking.

To use this principle, don’t overdo it. If everything stands out, nothing does. Save bold designs for the elements that truly matter, like calls to action or critical warnings.

22. Zeigarnik effect

The Zeigarnik effect is like an unfinished song stuck in your head. It says people remember incomplete tasks better than completed ones. This happens because the brain hates loose ends and keeps reminding you until the job is done.

In UX, this is why progress trackers work so well. Seeing an unfinished bar motivates users to keep going until they reach the end. Similarly, a notification badge (like a red dot on an app icon) nudges users to take action so they can “clear” it.

To use this, give users visual cues that show unfinished tasks. Use reminders, progress bars, or notifications to keep them engaged and on track.

23. Anchoring bias

Anchoring bias is when people rely too much on the first piece of information they get. This “anchor” shapes how they think about later info, even if it’s less relevant or useful. For example, if a price tag shows an item was originally $100 but is now $50, the $100 anchor makes the $50 feel like a great deal — even if the item’s real value is closer to $40.

In UX, this bias shows up in pricing strategies, like showing a higher “original price” next to a discounted one or starting with expensive options before showing cheaper ones. It also works in forms where default values (like donation amounts) set expectations for what users think is “normal.”

To use this, set an anchor that benefits your goal. Show premium options first to make standard ones look more appealing, or highlight the “usual” choice to guide users toward it. Just make sure your anchors feel honest and fair.

Additional principles

These are extra rules that don’t fit neatly into the other categories but are still key to creating great user experiences. They focus on efficiency, simplicity, and making tools work the way people expect.

24. Tesler’s law

Tesler’s law, or the law of conservation of complexity, states that every system has a certain amount of complexity, and you can’t eliminate it—you can only shift where it lives. In UX, this means the designer decides whether to make things simple for the user or take on the complexity behind the scenes.

For example, think about a ride-hailing app. All the user has to do is enter a destination and click “Book a ride.” Behind the scenes, the app calculates routes, matches you with a driver, and processes payments. The complexity is hidden from the user.

To apply Tesler’s law, keep interfaces simple by handling complexity on the backend. Make tasks intuitive for users, even if it means extra effort for the system or developer.

25. Occam’s razor

Occam’s razor is like the saying, “The simplest solution is often the best one.” It comes from philosophy, but in UX, it means you should always aim for the simplest design that still gets the job done.

Imagine setting up a piece of furniture. If the instructions give you ten steps when three would work just as well, you’d feel frustrated. The same goes for user experiences: extra complexity only creates confusion.

To apply this, strip away unnecessary elements, features, or steps. Focus on what users need to complete their goals and avoid overcomplicating things. A clean interface not only looks better but also makes users feel confident and in control.

26. Doherty threshold

The Doherty threshold is all about speed. It says that users feel most satisfied when a system responds in under 400 milliseconds. If the response time is faster than this, users feel like they’re in control. If it’s slower, they might get frustrated or lose focus.

Think about typing into a search bar. If the results appear instantly, it feels smooth and seamless. But if there’s a noticeable delay, you start clicking impatiently or lose trust in the system.

To apply this, optimize your system to respond quickly. For tasks that take longer than 400ms (like loading a large file), use loading animations or progress indicators to reassure users that things are working. And do what you can to get your site speed up. 

27. Pareto principle

The Pareto principle, or the “80/20 rule,” says that 80% of outcomes come from 20% of causes. In UX, this often means 80% of user actions happen on just 20% of your interface.

Think of a TV remote. You probably use only a handful of buttons — volume, power, and channel — while ignoring most of the others. The same goes for websites or apps. Users typically rely on a few key features and skip the rest.

To apply this, identify the 20% of features your users care about most and prioritize them. Make those features prominent and easy to access while minimizing or simplifying less-used options.

28. Postel’s law

Postel’s law, also known as the “robustness principle,” comes from networking but applies beautifully to UX. It says, “Be liberal in what you accept and conservative in what you send.” In other words, your system should handle user input flexibly but provide clear and consistent output.

Think of a search bar. If a user types “shirt-size-large” instead of “large shirt,” a well-designed system should still understand what they mean and return the right results. But the output (like product listings) should always follow a clean and predictable format.

To apply Postel’s law, design for human error. Anticipate different ways users might interact with your system and handle them gracefully. This makes your interface feel forgiving and user-friendly.

How to apply the laws of UX to your designs

The laws of UX aren’t just abstract ideas — they’re practical tools to help you create better designs. Whether you’re planning a new app or tweaking a website, use these principles to guide your decisions.

Start by understanding your users. Which laws matter most for their needs? For example, if you’re designing a checkout flow, focus on principles like Hick’s law (to limit choices) and the goal-gradient effect (to motivate users to finish).

Here’s a list of questions to guide you when applying the laws of UX to your designs:

• What is the user’s primary goal?
  (This helps determine which law supports the user’s journey, like the goal-gradient effect or Hick’s law.)
• What tasks or decisions might overwhelm the user?
  (Consider laws like Hick’s law to simplify choices or the paradox of choice to reduce decision fatigue.)
• How can I guide the user’s attention?
  (Think about Fitts’s law for clickable elements, anchoring bias for setting expectations, or Gestalt principles for grouping and focus.)
• Are there opportunities to motivate or nudge the user?
  (Use the Zeigarnik effect with progress indicators or the scarcity effect to encourage action.)
• Does my design create trust and credibility?
  (Apply Jakob’s law by sticking to familiar patterns or the aesthetic-usability effect to make the design visually appealing.)
• Am I showing too much information at once?
  (Use progressive disclosure or Miller’s law principle of chunking to make content easier to process.)
• How can I make the experience feel intuitive?
  (Rely on heuristics like Jakob’s law for familiarity or the law of proximity for organizing related elements.)
• What emotion or impression am I creating?
  (Think about the aesthetic-usability effect to make the design feel more pleasant or peak-end rule to leave a positive lasting impression.)
• Am I reducing friction where it matters most?
  (Apply Fitts’s law to place key actions within easy reach or Tesler’s law to avoid adding unnecessary complexity.)
• What cognitive biases might influence user decisions?
  (Consider anchoring bias, the framing effect, or loss aversion to shape how users perceive choices.)

Remember, these laws aren’t rigid rules — they’re guidelines. Combine them, test them, and flex them to your specific project. The goal is always the same: to create experiences that feel intuitive. 

Use diagramming tools for smarter, cleaner designs 

Diagramming tools can make it easier for your UX team to apply these principles. Visualizing user flows, grouping related elements, and mapping out task hierarchies can help you spot opportunities to simplify and refine your design. These tools let you experiment with layouts, relationships, and patterns before diving into development, ensuring your designs align with the laws of UX from the start. Ready to take Cacoo for a spin? Try it for free today!