🔍 Paraphrase Comparison Tool

The Paraphrase Comparison Tool uses a longest common subsequence (LCS) algorithm to analyze two texts — an original and its paraphrase — at the word level. It identifies which words remain unchanged, which have been removed or replaced in the original, and which have been added or substituted in the paraphrased version. The tool then highlights these differences with intuitive color coding and calculates a similarity percentage to help you quickly assess how thoroughly a text has been rewritten.

There is no universal threshold, but general guidelines suggest: a similarity score below 30% indicates a thorough rewrite with substantial original expression; 30–60% suggests moderate paraphrasing — acceptable in most academic and professional contexts with proper citation; above 60% may be too close to the original and could raise plagiarism concerns, especially in academic settings. Always aim to transform both the structure and vocabulary of the source text, not just swap individual words.

Paraphrasing restates the original text in your own words while preserving its full meaning and roughly the same length — every key point is retained. Summarizing, on the other hand, condenses the text to only the most essential ideas, significantly shortening it. A paraphrase answers "what did the author say in detail?" while a summary answers "what was the main point?" Our tool is designed for paraphrase comparison, helping you see exactly how wording and phrasing have changed between two versions of similar length.

Yes — by showing you exactly which parts of your paraphrase remain too similar to the original, this tool acts as a self-check before submission. If the similarity percentage is high and large sections are marked as "matched," you'll know you need to revise further. However, please note: this tool is a writing aid, not a guarantee against plagiarism. Always cite your sources properly, and use the tool alongside your own judgment and institutional guidelines.

The best paraphrasing combines multiple techniques: (1) Synonym substitution — replace words with accurate alternatives; (2) Sentence restructuring — change active to passive voice or vice versa, alter clause order; (3) Word form changes — convert nouns to verbs, adjectives to adverbs; (4) Breaking or combining sentences — split long sentences or merge short ones; (5) Using different transition phrases. The most effective paraphrases use 3 or more techniques simultaneously, which naturally lowers the similarity score on our tool.

Yes. Because the tool performs exact word matching (case-insensitive), any synonym that is a different word will be flagged as a change — the original word appears highlighted in red as "removed," and the synonym appears in green as "added." This is actually a strength of the tool: it visually confirms that a synonym replacement has indeed occurred, helping you verify that you've made genuine lexical changes rather than just rearranging the same words.

Paraphrasing without proper citation is considered plagiarism — even if you've changed every word. The ideas still belong to the original author. However, paraphrasing with appropriate attribution is a legitimate and essential academic skill. The key distinction: plagiarism is presenting someone else's ideas as your own, regardless of wording. Always cite your sources, and use this tool to ensure your paraphrase is sufficiently transformed in both language and structure.

The tool performs word-level comparison, which means: (1) It does not understand semantic meaning — a complete sentence restructure with the same words would show high similarity; (2) Very long texts (over 2,000 words) may be truncated for performance; (3) Punctuation changes are captured but minor formatting differences (like extra spaces) are normalized; (4) It cannot assess the quality or accuracy of a paraphrase — only the degree of lexical difference. For a full plagiarism check, use dedicated software like Turnitin or Grammarly alongside this tool.