Skip to content

Koala AI's biggest release yet: Brand DNA, your AI SEO agent, and Content Calendar Autopilot. See what's new →

Back to Tools

Free Plagiarism Checker

Scan any text for potential overlap with publicly indexed sources, attribution issues, and unoriginal phrasing.

Get specific suggestions for rewriting any sections that need attention.

What this checker does (and doesn't do)

This tool uses an LLM to review your text for passages that look problematic (verbatim definitions, unattributed statistics, common stock phrasing) and gives you concrete rewrites for each one.

It is not a substitute for a paid web-indexed plagiarism scanner like Copyscape or Turnitin. Use this for fast, first-pass review during drafting. If you're publishing content where original-source compliance matters (academic, legal, regulated industries), use a dedicated paid service before publication.

When to use it

  • Reviewing AI-generated drafts before adding your own edits and published voice.
  • Checking guest posts and contributor submissions for accidental copying.
  • Auditing older content to catch unattributed stats that have spread across the web since publication.

Frequently asked questions

Does this scan the entire web like Copyscape?

No, and we're upfront about that. True web-wide plagiarism scanning requires a paid indexed-content service. This tool uses an LLM to flag passages that look problematic (verbatim definitions, common stock phrasing, unattributed stats). It's best used as a first-pass review during drafting, not as a final compliance check before publishing high-stakes content.

What kind of issues does it catch?

Verbatim text from common reference sources (Wikipedia-style definitions, dictionary entries, frequently-repeated marketing copy), statistics quoted without attribution, and phrasing that mirrors well-known industry boilerplate. It will not catch deeply-paraphrased copying from obscure sources.

Should I be worried about AI-generated content?

Google's stance, as of 2026, is that AI content is fine as long as it's helpful and original. AI-generated text isn't inherently plagiarism, but if you're producing text at scale, you should still verify that it isn't unintentionally close to existing published content on the same topic.

Related free tools

Paraphrasing Tool

Rewrite flagged passages while keeping the meaning.

Readability Analyzer

Pair with readability checks for a full review.

Final Draft

Polish your draft into a publish-ready version.

Free AI Writer

Draft original content from scratch.

Try KoalaChat

Need more advanced AI capabilities? KoalaChat offers GPT-5, real-time data, and more, all with a generous free tier.

Try KoalaChat

Try KoalaWriter

Need help with longer content? KoalaWriter helps you create blog posts, articles, and more with AI assistance.

Try KoalaWriter