Save Time and Frustration

Say No to Poorly Designed Products!

Save Time and FrustrationRegister for free
Back to index

ISO 9126

What is ISO 9126?

ISO 9126, introduced by the ISO (International Organization for Standardization) in 1991 and replaced by ISO 25010 in 2011, is an international standard for evaluating software quality. It defines six key characteristics: functionality, reliability, usability, efficiency, maintainability, and portability. These standards help ensure the software fulfills user needs, performs reliably, is user-friendly, operates efficiently, can be easily updated, and works across various environments.

glossary bee

The criteria of ISO 9126

  1. Functionality: Does the software provide the functions that meet user needs?
  2. Reliability: Can the software maintain its performance over time and under defined conditions?
  3. Usability: Is the software easy to understand, learn, and use?
  4. Efficiency: Does the software provide good performance without wasting resources?
  5. Maintainability: How easy is it to modify the software for changes or fixes?
  6. Portability: Can the software be easily transferred to different environments?

Each characteristic is associated with a set of metrics that can be used to measure the quality of the software in that aspect.


How is ISO 9126 standard useful for testers?

  • From a tester’s perspective, the ISO 9126 standard is highly beneficial. It offers clear guidelines and criteria for assessing software quality, making it easier to identify any shortcomings or areas for improvement. 
  • By evaluating a software product against these defined characteristics, testers can ensure that the software meets the required standards of quality, thereby aiding in delivering a product that ensures user satisfaction and robust performance. 
  • The distinct criteria of ISO 9126 also help in streamlining the testing process, facilitating focused and efficient testing practices.

Achieve your Research Objectives with UXtweak!

Transform your research objectives into actionable insights with our research tools!

Register for free


What is the replacement of ISO 9126?

The replacement for ISO 9126 is ISO 25010. The ISO 25010 expanded upon ISO 9126 by defining eight major software quality characteristics, introducing a detailed “Quality In Use” model, differentiating between system and software quality, and considering data and information quality.

What is the difference between ISO 9126 and ISO 25010?

ISO 9126 and ISO 25010 are standards developed by the International Organization for Standardization (ISO) to assess software quality. While ISO 9126, established in 1991, offers 6 primary characteristics and 27 sub-characteristics, its successor, ISO 25010, expands on this with 8 primary characteristics and 31 sub-characteristics, providing a more comprehensive framework. Botella et al. (2004) identified limitations in ISO 9126 due to its general applicability, making ISO 25010 a more complete and specific tool for assessing software quality.

Learn More


Usability Testing Guide

Usability Testing Guide

An ultimate guide to usability testing that contains everything you need to know about the method, its nuances, types, advantages and disadvantages. Learn how to write a usability testing script, grab an editable usability testing template and follow our step-by-step process for creating a usability testing study.

A Complete Guide to UX Audit: Templates + Checklist

A Complete Guide to UX Audit: Templates + Checklist

Uncover the importance of UX audits, outlining the key steps and methodologies involved in assessing usability, accessibility, and overall UX effectiveness. Discover how a UX audit conducted by a domain expert can uncover valuable insights to drive meaningful improvements and optimize the user experience of your digital products.

SUS: Enhancing UX with the System Usability Scale

SUS: Enhancing UX with the System Usability Scale

Dive into the System Usability Scale (SUS) and understand its significance in measuring user perceptions of usability. This article explains the SUS questionnaire and its role in assessing the overall usability of a system or product. Learn how to effectively administer and interpret SUS scores to get actionable metrics on product performance.

Iterative Design