Difference Between Bug and Defect

Difference Between Bug and Defect

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Anshuman Singh
Senior Executive - Content
Updated on Jun 12, 2023 15:51 IST

Do you know the difference between a bug and a defect? The main difference between bug and defect is that a bug is an error in the software that causes it to malfunction. In contrast, a defect is a flaw in a product that reduces its value or usability. There are more difference between these two terms. In software development both are responsible for causing issues in software programs, but they are not the same thing. Let’s understand!


You’re using a cutting-edge fitness tracking app to monitor your daily activity, only to find that the step count is consistently inaccurate. Is it a bug or a defect? Understanding bugs and defects differences is crucial for delivering impeccable software.

Explore a scenario where a popular e-commerce platform encounters a bug that causes customers to be charged multiple times for a single purchase. While a defect in a navigation app leads users to incorrect destinations. Gain clarity on these concepts and discover how to prevent and address them, ensuring a seamless software experience for users.

In this article, we will understand the difference between defects and bugs using real-world examples. But, before we begin, let’s review the list of topics listed under the table of contents (TOC) we will discuss in this article.

Table of Contents (TOC)

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Difference Between Bug and Defect

For a better understanding, let’s explore the bug and defect difference in a tabular format. Here’s the table:

Benchmark Bug Defect
Definition An error is a fault in the software/code that causes unexpected behaviour. A defect is a flaw in a product that reduces its value or usability.
Cause Programming error Design or requirement flaw
Occurrence Can occur during any stage of testing or development Mostly found during testing
Fixing Requires debugging Requires reworking the design or requirements
Responsibility Usually, the developer’s responsibility. Shared responsibility between the development and testing teams.
Can be classified based on Minor or major bug Impact and urgency

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What is a Bug?

Bug Definition: A bug is a fault in the software/code that causes it to malfunction.

In layman’s terms, a bug is a mistake in the software that makes it not work as it should. Bugs can happen for different reasons, such as mistakes made when writing the code, wrong assumptions about how people will use the software or changes to the environment where the software runs. Developers can discover bugs while testing the software or by customers after it’s released.

There are different types of bugs, such as Algorithmic, Logic, and Resource bugs.

  • Algorithmic bugs occur because of mistakes in the math or logic used to make the software work.
  • Logic bugs occur when the software doesn’t work properly because of code mistakes.
  • Resource bugs occur when the software uses too much memory or other resources, slowing down the computer or causing it to crash.

What is a Defect?

Defect Definition: A defect is a flaw in a product that reduces its value or usability.

In layman’s terms, a defect is a problem with a software program discovered after being released for use by the public. If a feature does not work as it is supposed to, it is considered a defect. Defects can hurt how the software performs and how easy it is to use.

Defects can occur for a variety of reasons, such as:

  • Mistakes in design.
  • Incorrect assumptions about how the software will be used.
  • Changes in the environment in which the software is used, etc.

It is important to remember that defects, unlike bugs, can be difficult to identify and fix.

Different types of defects exist, such as Integration, Performance, Design, and Logical.

  • Integration defects occur when different software parts do not work together properly.
  • Performance defects happen when the software does not perform as expected in certain conditions.
  • Logical defects are code errors caused by misunderstandings about what the software is supposed to do.
  • Design defects occur when the software’s appearance or functionality is incorrect and can negatively affect a company’s reputation.

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Ways to Prevent Bug and Defect

Following best practices is crucial to prevent defects and bugs and ensure high-quality software. Here are some key strategies:

  • Code Reviews: Conduct thorough code reviews to catch potential issues early. Reviewers can identify bugs, suggest improvements, and ensure adherence to coding standards.
  • Automated Testing: Utilize automated testing frameworks to validate functionality, performance, and reliability. Automated tests like unit and integration tests help detect bugs at various application levels.
  • Quality Assurance Processes: Implement comprehensive QA processes, including functional testing, performance testing, security testing, and usability testing. Follow well-defined test plans and execute tests regularly to identify and address bugs before release.
  • Agile and DevOps Methodologies: Adopt Agile or DevOps methodologies for iterative development and continuous integration. These practices enable early bug detection and resolution, ensuring higher software quality.
  • Effective Communication and Collaboration: Encourage open communication among team members to discuss requirements, design decisions, and potential risks. Regular team meetings and feedback sessions foster an environment for prompt bug identification and resolution.
  • Documentation and Knowledge Sharing: Maintain comprehensive documentation of requirements, design specifications, and coding standards. To prevent common pitfalls, promote knowledge sharing through wikis, code documentation, and lessons-learned sessions.

Key Differences Between Bug and Defect

Here are the key differences between bug and defect:

  • Programming errors cause bugs, while defects are caused by design or requirement flaws.
  • Defects are mostly found during testing, whereas bugs can occur at any stage of testing or development.
  • Bugs require debugging, while defects require reworking the design or requirements, making it a resolution process.
  • Bugs are usually the developer’s responsibility, while defects are shared between the development and testing teams.
  • Defects can be classified based on their impact and urgency, while bugs can be classified based on whether it is a minor or major bug.
  • A bug is a fault in the software/code that causes it to malfunction. In contrast, a defect is a flaw in a product that reduces its value or usability.

Must explore: Understanding the Different Levels of Testing in Software Development


This article has explored what bugs and defects are in software development. We have also explored their types and the difference between these terms in great detail. If you have any queries related to the article (Difference Between Bug and Defect), please feel free to send your queries to us in the form of a comment. We will be happy to help.

Happy Learning!!

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What is the difference between a bug and a defect?

The terms "bug" and "defect" are often used interchangeably in software development, but there is a subtle distinction between them. A bug refers to an issue or flaw in the software that causes it to behave unexpectedly or produce incorrect results. On the other hand, a defect is a broader term that encompasses any deviation from the expected behavior, including bugs. In essence, all bugs are defects, but not all defects are necessarily bugs.

How is bug different from a defect?

The differentiation between a bug and a defect can vary depending on the context and the specific usage within an organization. However, one common approach is to consider a bug as a specific manifestation of a defect. A bug typically refers to an identified and reproducible error in the software, while a defect can be a more general term encompassing any flaw or deviation from the desired functionality.

Can a defect be considered as a bug?

Yes, a defect can be considered as a bug. As mentioned earlier, a bug is a specific occurrence or manifestation of a defect. When a defect manifests itself in a way that causes the software to behave incorrectly, it is referred to as a bug. So, a defect can be considered a more general term, while a bug is a specific type of defect.

Are bugs and defects treated differently in software development?

In most cases, bugs and defects are treated similarly in software development processes. Both require identification, tracking, and resolution. However, the terminology used may vary depending on the organization or project. Some teams may use the term "bug" exclusively, while others may adopt a broader usage of "defect." Ultimately, the specific terminology used does not significantly impact the overall process of identifying and resolving issues in the software.

Who fixes bugs and defects?

Bugs and defects are typically fixed by software developers or engineers responsible for the development and maintenance of the software. They identify, analyze, and resolve the issues to ensure the software functions correctly and meets the desired quality standards.

About the Author
Anshuman Singh
Senior Executive - Content

Anshuman Singh is an accomplished content writer with over three years of experience specializing in cybersecurity, cloud computing, networking, and software testing. Known for his clear, concise, and informative wr... Read Full Bio