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Free Plagiarism Detector, Verify Originality.

Identify possible matching sources for your text using AI analysis. Review confidence scores and matched excerpts, then verify every flagged URL independently.

0 / 5,000
TXT, DOCX, PDF, MD, CSV, TSV, HTML, JSON, XML up to 10 MB
Results

Potential matching sources will appear here

How it works

Three steps from draft to confidence.

1

Paste Your Text

Copy your essay, article, or blog draft into the editor. Up to 5,000 characters per check.

2

AI Source Analysis

Our AI cross-references your text against its training knowledge to identify passages that may appear on published web pages.

3

Review Matched Sources

Examine each potential source, confidence score, and matched excerpt. Verify every URL independently before drawing conclusions.

Built for clarity, not false confidence.

Each result comes with context so you can make informed decisions about originality.

Source Detection

Identifies web pages that may contain wording similar to your input text.

Confidence Scoring

Each source includes a 0–100 confidence estimate so you can prioritize verification.

Broad Coverage

Draws on training knowledge spanning news, academic, and publishing domains.

Excerpt Matching

Shows the specific overlapping passage for each potential source.

Fast Analysis

Returns results in seconds with no manual search required.

Honest Limitations

Sources are estimates, not live web scans — always verify independently.

GPTHuman Plagiarism Checker demo showing source text, matched sources, and confidence scores

Know where your words may already live.

Use the checker for a first-pass review, then verify every flagged source in context. It does not replace professional plagiarism-detection software for high-stakes submissions.

  • Surfaces potential matching sources with confidence scores
  • Shows the exact overlapping excerpt for each match
  • Free to use with no account required
  • Results include an honest disclaimer about limitations

Plagiarism Checker FAQ

The tool sends your text to an AI model that cross-references it against knowledge from its training data. It identifies passages that may appear on published web pages and returns potential source URLs, matched excerpts, and confidence scores. It does not perform a live web crawl.

Yes. The basic plagiarism checker is free to use with no account required. Per-request limits may apply during high-traffic periods.

Sources are best-effort estimates based on the AI model's training knowledge. Confidence scores indicate how certain the model is, not a guarantee. Always verify every flagged URL independently before acting on the results.

No. The checker relies on the AI model's training knowledge, not a real-time web crawl. It may miss recently published content or niche sources that were not in the training data.

You can check essays, blog posts, articles, reports, emails, product descriptions, and any other written text up to 5,000 characters per check.

Text is sent to the AI provider for analysis and is not stored by GPTHuman after the response is returned. Review the provider's data policy for their retention practices.

Check every draft before you publish.

Identify potential matching sources for free, then verify each one in context.

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