Microsoft will retire the Similarity Checker in Word on October 3, 2026, removing the plagiarism-detection tool from the Microsoft Editor experience. The change means users who depend on the feature to compare text against online sources will need to find alternatives before the cutoff date.

What You Need to Know

Similarity Checker launched in 2020 and used Bing Search to generate a percentage score indicating how much text overlapped with online content. Its retirement does not affect Word's citation tools, grammar checking, or the broader Microsoft Editor. Although Microsoft has not shared usage statistics, the company indicated the tool was not widely adopted. Users in education or publishing who relied on Similarity Checker should evaluate third-party services like Turnitin before October 2026.

Background of a Feature

The Similarity Checker was introduced by Microsoft in 2020 as a way to help writers check originality. It scanned text against web sources and returned a similarity percentage, allowing users to add citations or rewrite passages. The company described it as a tool that could “aid writers in focusing less on the mechanics of writing, and more on the content.”

This feature ran through the Microsoft Editor pane in Word, but it never reached the level of integration that other tools achieved. Although Microsoft invested in the checker during its early years, usage appears to have declined as the company shifted focus toward Copilot, its AI assistant embedded across Microsoft 365.

  • What is changing: Similarity Checker will stop working on October 3, 2026 and will no longer appear in the Editor menu.
  • What remains unchanged: Word's citation builder, spelling and grammar checking, and Copilot will continue to function.
  • Who is affected: Organizations that integrated Similarity Checker into editorial workflows need to find alternatives.

Why This Matters

The retirement signals that Microsoft is doubling down on AI-powered writing aids at the expense of standalone detection tools. Copilot can generate and rewrite text, but the company has warned that it is “not intended to serve as a formal similarity, plagiarism, or originality validation tool.” This creates a gap for users who need verification that content is original, especially in academic and professional publishing.

Plagiarism detection has become more critical as AI-generated text proliferates. Competitors like Turnitin have added AI-detection features, but Microsoft's decision to remove Similarity Checker without replacing it with a comparable tool leaves Word users without a native option. Organizations may need to license third-party services or rely on manual review, adding cost and friction to their workflows.

Although Microsoft has stressed that this change “allows us to focus on experiences and capabilities that are more broadly used,” the move raises questions about the future of built-in editorial integrity tools in productivity software. As the company pours resources into Copilot, features that serve niche but important use cases are being pruned.

Looking Ahead

Users should plan for the transition now. The Similarity Checker will remain accessible until October 3, 2026, after which it will be disabled permanently. Those who need formal similarity checking should evaluate services like Turnitin or consider standalone plagiarism checkers. Word itself will not lose any core editing capability, but the retirement underscores a broader trend: Microsoft is shaping its productivity suite around AI, and tools that do not fit that vision are being phased out.