DIN EN ISO 9241 – Overview

The ISO 9241 series of standards is the international standard for the ergonomics of human-system interaction - with central importance for usability and UX.

What is DIN EN ISO 9241?

DIN: Deutsches Institut für Normung, German Authority for norms and standards EN: European Norm
ISO: International Standards Organisation → An internationally recognized series of standards that has been adopted at European and national level.

What does ISO 9241 regulate?

The DIN EN ISO 9241 standard provides guidelines for the design of interactive systems - with the aim of improving the usability and user-friendliness of software and hardware. It addresses both technical and psychological aspects of interaction and defines standards for user-centered design.

For example, the standard describes how user interfaces should be designed so that they are easy to understand, efficient to operate and pleasant to use. Accessibility requirements and ergonomic working conditions are also covered.

Structure of the standards series

The standard has a modular structure and is divided into individual parts, each of which covers different aspects. The following are particularly relevant for UX and usability:

📘 ISO 9241-11 - Define suitability for use

This part provides a definition of usability as the extent to which a product can be used efficiently, effectively and satisfactorily by specific users in a specific context of use.
Example: A booking system for rail travel should enable users to search for connections and book tickets quickly and without errors - regardless of whether they are at their desk or on the move.

🧩 ISO 9241-110 - Design dialog principles

Seven basic principles__ for user-friendly dialogs are described here, including controllability, conformity to expectations and fault tolerance.
These principles help, for example, to design forms, navigation or feedback messages in such a way that they correspond to the users’ mental models.

🧠 ISO 9241-210 - Anchoring user-centered design in processes

Part 210 describes a iterative approach for the development of user-centered products. Central elements are the analysis of the context of use, the involvement of users during development and the continuous testing of prototypes.
Example: When developing a health app, real patients are involved in design decisions at an early stage.

♿ ISO 9241-171 - Implementing accessibility

This section focuses on Software accessibility, e.g. by supporting screen readers or high-contrast displays.
An accessible login process with easy-to-read text and clear keyboard controls meets the requirements of this part of the standard.

Why is ISO 9241 so important?

The series of standards has both practical and legal relevance:

It is often used as a reference in tenders and product liability.
It serves companies as a ** guideline for UX processes and quality standards**.
It creates a common language between designers, developers, researchers and stakeholders.
It helps to set up usability tests in a structured way - with reference to the context of use and defined quality objectives.

Best Practice

ISO 9241 is not a test catalog or a rigid standard. It offers an orientation framework that should be adapted and selectively applied depending on the project.

Conclusion

DIN EN ISO 9241 is the backbone of user-centered design.
It combines normative orientation with application-oriented recommendations - and is therefore indispensable for all those who develop products that not only work, but are also popular.

Take Home Message

ISO 9241 is the backbone of usability - normative, flexible and practical.

Last modified: 17 June 2025