3 laws of Usability – as defined by Steve Krug

Steve Krug is a usability and user experience (UX) consultant best known for his popular book Don’t make me think.

Before looking at the three usability laws, let’s first define usability.

Usability: The quality or state of being usable

(i.e. is it easy to use and complete tasks?)

Usability Law 1: Don’t Make Me Think

The key in meeting this first law is to keep things simple & consistent. That’s it.


“Simplicity is a design principle that considers the user’s goals and provides the simplest way to achieve those goals. Simplicity is not just about using fewer colors or adding a lot of white space in your design, it is something that requires you to understand your user’s needs and provide a minimal design to fulfill them.”

Simplicity in design: https://uxdworld.com/2019/09/09/simplicity-in-design/
(UX Design World)


“[…] usability and learnability improve when similar elements have consistent look and function in similar way. When consistency is present in your design, people can transfer knowledge to new contexts and learn new things quickly without pain. This way they can focus on executing the task and not learning how the product UI works every time they switch the context.”

Anton Nikolov, Design principle: Consistence

Usability Law 2 : It doesn’t matter how many times I have to click, as long as each click is a mindless, unambiguous choice

If users believe they are getting closer to a satisfactory results, they will keep on clicking. There is no official rule that says important information should be 3 clicks away (see The 3-Click Rule for Navigation is False by Nielsen Norman Group). It’s not supported by data.

“After analyzing the satisfaction data, we still found no evidence for the Three-Click Rule. When we looked at the percentage of users who were unsatisfied, our data showed there was little variation (between 46% and 61%) between different lengths of clickstreams. Fewer clicks do not make more satisfied users.”

Joshua Porter, Testing the Three-Click Rule

Usability Law 3: Get rid of half the words. Then get rid of half of what’s left

Did you know that too much content can actually overwhelm users and make them unfocused?

Remove the extra blah-blah by keeping your content short and concise. Start with your important information at the top of the page, make use of headings, lists and visuals. Add white space in your design to give users breathing room.

The result will be a page easy to scan, consume and digest while being accessible to a wide audience.

Take a look at this well-explained video about white space.

Brendan Colarusso, How to Use White Space in UI Design (UI Principles Series)

Related resources

In this interview (March 2021) with Brave UX, Steve Krug reflects on 30+ years of contribution to the field of UX.
Steve Krug explains why usability testing is so important and runs through some tips for improving your own usability tests.