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Plagiarism Percentage Checker

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Get an exact plagiarism percentage score for your text with source analysis

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Paste at least 30 words and click Check Plagiarism to scan for copied content

How It Works

  1. 1

    Paste Your Text

    Copy and paste the text you want to check -- essays, reports, blog posts, or any written content. Minimum 30 words required; 50+ words recommended for the most accurate results.

  2. 2

    Scan for Matches

    The tool extracts key phrases from your text and searches the web for matches. It also analyzes sentence structure, cliche density, and vocabulary patterns to estimate originality.

  3. 3

    Review Results

    Get an overall originality score, matched source URLs with similarity percentages, and per-sentence analysis highlighting flagged passages. Use the Humanize feature to rewrite flagged text automatically.

Knowing your plagiarism percentage before submission can mean the difference between a passing grade and an academic integrity violation. Many institutions set specific thresholds -- 15%, 20%, or 25% maximum similarity -- and exceeding them triggers automatic review. But plagiarism percentage alone doesn't tell the full story: a 20% similarity score might include properly cited quotes, common phrases, or bibliographic entries that aren't actually plagiarism.

Coda One's Plagiarism Percentage Checker gives you an overall originality score (which inversely represents the plagiarism percentage) along with the context you need to understand what's driving the number. If your text scores 75% originality, the corresponding 25% is broken down into specific matched sources with their individual similarity percentages and the exact sentences that triggered each match.

This granular breakdown is what makes a percentage meaningful. A 25% similarity score where all matches come from properly cited sources in your bibliography is very different from 25% where matches come from uncredited web pages. The per-sentence analysis lets you distinguish between these scenarios: review each flagged sentence, check the matched source, and determine whether you need to add a citation, rewrite the passage, or simply note it as a coincidental phrase match. Then re-run the check to see your updated percentage.

Frequently Asked Questions

What plagiarism percentage is acceptable?
Most universities accept 15-25% similarity, but this varies by institution and assignment type. Research papers with many citations naturally have higher similarity percentages. The key is context: properly cited quotes and common academic phrases shouldn't count against you, even if they contribute to the overall percentage. Check your institution's specific policy.
Why is my plagiarism percentage high even though I wrote everything myself?
Several factors can inflate your percentage: common phrases and idioms that appear on many websites, well-known definitions or facts stated in standard ways, properly cited quotes (which are matches but not plagiarism), and coincidental phrasing that happens to match existing content. Review the per-sentence analysis to identify what's actually driving the percentage.
How do I lower my plagiarism percentage?
Focus on the flagged sentences shown in the per-sentence analysis. For each flagged sentence: rewrite it in your own words (changing both structure and vocabulary), add proper citation if it's a quote, or rephrase common phrases to be more specific and unique. Re-run the check after making changes to verify the percentage dropped.
Does the percentage include properly cited quotes?
Yes, the web matching will find text that matches online sources regardless of whether it's cited in your document. However, the per-sentence analysis helps you distinguish: if a flagged sentence is a properly cited direct quote, that's not plagiarism -- it's expected similarity. Focus your revision efforts on flagged sentences that are not properly attributed.
How is the originality percentage calculated?
The originality score combines web source matching results (how many of your sentences have matches online) with structural analysis (vocabulary richness, cliche density, sentence diversity). The score ranges from 0-100%, where 100% means no matches found and high textual originality. Your plagiarism percentage is roughly the inverse: 100% minus your originality score.

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