The usability Rule of 7 is a widely accepted principle in user experience (UX) design that states people can hold approximately 7 pieces of information in their short-term memory. This principle has important implications for designing interfaces that are easy to use and understand. The Rule of 7 provides practical guidance to UX designers, developers and product managers on limiting the amount of information presented to users at one time. Adhering to the Rule of 7 creates a better user experience by reducing cognitive load and confusion.
What is the Rule of 7?
The Rule of 7, also known as Miller’s Law, states that the average person can only keep 7 (plus or minus 2) pieces of information in their short-term memory at one time. This concept was put forth in 1956 by psychologist George Miller in his research on immediate memory span. Miller’s research showed that most adults can store between 5 and 9 items in their short-term memory. This suggests that 7 is the optimal number of units for users to comfortably process without being overwhelmed.
The Rule of 7 has become a widely accepted principle in user experience design. It recommends that designers limit the amount of information presented to users at any given time to 7 items. This includes navigation menus, form fields, images, options, notifications and more. By sticking to around 7 pieces of information, designers can create interfaces that are scannable, easy to understand and minimize cognitive strain on users.
Why the Rule of 7 Matters
The Rule of 7 is important for UX designers to follow because it reduces cognitive load on users. Cognitive load refers to the total amount of information the brain is processing at one time. When interfaces bombard users with too many options and pieces of data at once, it creates unnecessary cognitive load. This leads to:
- Overwhelming users
- Increasing confusion
- More errors
- Reduced task completion
- Lower satisfaction
However, when designers limit the information presented to match the 7 item capacity of short-term memory, it minimizes cognitive strain. This allows users to:
- Process information more easily
- Understand choices faster
- Feel less overwhelmed
- Make fewer errors
- Complete tasks quicker
Adhering to the Rule of 7 creates a positive user experience. Interfaces become more scannable, comprehensible and usable when the amount of information is limited to 7 units.
Applying the Rule of 7
Here are some examples of how UX designers and product managers can apply the Rule of 7:
Navigation Menus
Navigation menus should aim to have around 7 main links. Research shows that mega-menus with endless links and sublinks increase cognitive strain. Menus with 7 top level categories help users quickly scan and understand available options.
Form Fields
Forms should try to limit the number of fields to 7 core pieces of information. Too many fields overwhelm users, particularly on mobile. Sticking to 7 key fields creates simpler forms that users can easily comprehend and fill out.
Product Page Content
Product pages should highlight no more than 7 essential features or benefits of that item. More than 7 key points becomes difficult to retain. Around 7 concise points are more memorable.
Dashboard Metrics
Dashboards should focus on displaying 7 key metrics or KPIs. Dashboard creators often overload with dozens of graphs, charts and figures. This creates cognitive overload. 7 well-chosen metrics provide the essential insights users need.
Email List Content
Email lists and newsletters should contain roughly 7 articles or pieces of content. Long daily email lists with endless content cause many users to disengage. Around 7 stimulating pieces encourage more opens and clicks.
Search Results
Search results should aim for 7 top matches. Presenting too many low-relevancy results forces users to think harder. Showing 7 highly relevant results helps users swiftly scan and select.
App Features
Apps should try to limit features to 7 core functions, especially early on. Loading apps with too many features overwhelms users. Starting with 7 key features that address essential needs is best.
Using Chunking and Hierarchy
Two related UX design concepts that complement the Rule of 7 are chunking and hierarchy.
Chunking involves breaking down information into smaller digestible pieces or “chunks” to reduce cognitive load. This technique can be used to apply the Rule of 7, by separating content into chunks of 7 or fewer points.
Hierarchy creates structure and order through clear rankings of information from most to least important. Hierarchy helps highlight the 7 most critical pieces of content users need to know first.
Both chunking and hierarchy make interfaces easier to scan and comprehend by guiding users to the 7 most essential bits of information first. They work hand-in-hand with the Rule of 7.
Limits of the Rule of 7
While the Rule of 7 is useful for simplifying most interfaces, there are some exceptions. In certain complex applications, strictly limiting to 7 items may be unrealistic. Some contexts may require presenting slightly more than 7 pieces of data simultaneously. Designers need to balance simplicity with practical functionality.
Additionally, the ability to process information varies by individual. Certain demographics like younger or older users may be able to comfortably process fewer or more than 7 units of data. There is no one size fits all approach. Testing interfaces with real users is always essential.
The Rule of 7 should act as a general guideline that is helpful in most situations, but may need flexibility in certain complex contexts. UX designers should rely on user testing and feedback to determine optimal information loads.
Summary
The Rule of 7 is an established mental model for simplifying user interfaces. By limiting the amount of information presented to around 7 items, designers can reduce cognitive strain for users. This enhances usability by allowing users to easily scan, comprehend and act on interfaces.
While not an absolute rule, striving for 7 pieces of data generally optimizes comprehensibility. Combined with other techniques like chunking and hierarchy, the Rule of 7 creates interfaces that feel simple, intuitive and user-friendly. This principle remains highly relevant for UX designers in crafting digital products today.
| 7 Items or Less is Best for: |
|---|
| Navigation Menus |
| Form Fields |
| Product Page Features |
| Dashboard Metrics |
| Email List Content |
| Search Results |
| App Features |
References
Miller, George A. “The magical number seven, plus or minus two: Some limits on our capacity for processing information.” Psychological review 63.2 (1956): 81.
Cowan, Nelson. “Chapter 20 – Short-term memory, working memory, and attention.” In Alan Baddeley, Michael W. Eysenck, and Michael C. Anderson, eds. Memory (Psychology Press, 2009).
Alvarez, G. A., & Cavanagh, P. (2004). The capacity of visual short-term memory is set both by visual information load and by number of objects. Psychological Science, 15(2), 106-111.
Nielsen, Jakob, and John Morkes. “Applying writing guidelines to web pages.” (1997).
