Free plagiarism checker.
Upload a document or paste your text — get a defensible plagiarism + AI report in under a minute. 150 words free, no card, no signup.
Six engines.One defensible report.
Plagiarism report
A precise similarity score against 14B web pages, 500M texts and 25,000 journals — with the top matching sources surfaced for citation.
AI detector
Sentence-level fingerprinting flags reformulated, paraphrased and machine-blended paragraphs — fine-tuned weekly on every new GPT, Claude and Gemini release.
Per-paragraph evidence
Each match is anchored to a paragraph and a source. Compare side-by-side and decide what to cite, paraphrase or rewrite.
Self-plagiarism check
Upload your previous papers, a classmate's draft, or an internal corpus — and catch (self-)matches that public databases would miss.
See exactlywhat got matched.
Precise similarity percentage
An at-a-glance score, with the contribution of every matched source broken out beneath it.
Highlighted matches in context
Colour-coded passages inside your own document, each one tied back to the source it came from.
Side-by-side comparison
Read your paragraph against the original, line for line — without ever leaving the report.
Students, educatorsand teams that ship.
Self-check before you submit
Catch missing citations, accidental paraphrases and machine-blended sentences — before the grader does.
Grade with defensible evidence
Batch-scan submissions and get per-paragraph evidence you can hand to a student — or an integrity committee.
Protect your brand across every doc
Verify originality across internal documents, marketing copy and external reports — UI, API or your workflow.
Prove it's yours before you hit send
Attach the originality report to every delivery.
Start checkingQuestions aboutAI detection.
An AI detector evaluates patterns in submitted writing and estimates whether the text may have been generated by artificial intelligence. The result is probabilistic. It is not proof of authorship and should be reviewed together with the text, drafts, sources and writing context.
Quetxt analyzes the submitted text and reports AI-related indicators, including AI probability, Total AI rate and sentence-level probabilities. The report can highlight passages that deserve closer review, but it does not make a final decision about who wrote the text.
AI probability estimates how likely the submitted text as a whole may have been generated by AI. It applies to the overall text and should not be treated as a pass-or-fail verdict.
Total AI rate shows the share of sentences or passages that the system marked as possibly AI-generated. It is different from AI probability, which concerns the submitted text as a whole.
Individual sentences may receive their own probability. These results help a reviewer locate specific passages that may need closer attention instead of treating the entire document as one uniform result.
No. AI detection is probabilistic and cannot prove authorship. A report should be used as a review signal, not as definitive evidence that a person did or did not use AI.
Yes. A false positive occurs when human-written text is marked as possibly AI-generated. Formulaic wording, editing, technical prose, limited text length and other factors may affect the result.
Yes. False negatives are also possible. AI-generated text may not always be identified, especially after editing or when the submitted sample provides limited evidence.
No. Quetxt does not reliably identify a specific AI model or writing tool. The report evaluates writing patterns rather than proving that a named model produced the text.
No. AI detection and plagiarism checking analyze different things. AI detection evaluates writing patterns, while a plagiarism check looks for similarity to existing sources. Text may receive an AI-related result without matching any source, and a source match does not prove that AI was used.
You can check up to 150 words a day without registering or adding a card. After registration, the account receives a one-time 1,000-word allowance and a daily allowance of 300 words. The free allowance is shared between AI detection and plagiarism checking, and the amounts should not be assumed to combine into one guaranteed first-day total.
Yes. You can check up to 150 words a day without an account or payment card. Registration is required for the additional registered-user allowance and account features.
Quetxt supports DOCX, PDF, TXT, RTF and ODT files. You can also paste text directly into the checker.
A submitted check requires at least 100 characters. Very short samples may provide less context, so the result should be interpreted cautiously.
Yes. Quetxt supports up to 10 files in one check, with a maximum size of 24 MB per file. Pasted text and file upload are separate input methods and are not used at the same time.
Processing time depends on the length and complexity of the submitted text. A short document may finish in about 20 seconds, while a document of around 100 pages may take up to approximately 10 minutes. These are estimates, not guaranteed completion times.
Documents may remain available in an account until the user deletes them or deletes the account. They are not automatically added to the general comparison database. Deleted documents and deleted accounts are not retained in backups.
No. Submitted texts and documents are not used to train AI models.
The report can be exported as a PDF and can also be shared through a report link when those options are available in the completed report.
An AI score should not be the sole basis for an academic, disciplinary, employment or legally significant decision. Reviewers should consider the text, drafts, sources, assignment rules, writing process and other relevant evidence.
Yes. You can run only AI detection, only plagiarism checking or both analyses together. The results remain separate because the two systems answer different questions.
Quetxt supports checking text in more than 70 languages. This refers to text analysis and does not mean that customer support is available in every supported language.
