Plagiarism Checker Free — Originality Scanner
Paste or upload up to 150,000 characters to compare your text against web sources. You get an originality score and a list of matching source URLs.
Limitations: Only sources the provider can search are checked, so a high originality score isn’t proof that nothing was copied. Cited quotes also count as matches. How results can be wrong →
Scan your document for plagiarism
Check Originality
How the Plagiarism Checker Works
Your text is sent to third-party plagiarism-checking providers, which compare it with web sources. Rather than a single originality number, you also get each matching source with its own match percentage.
Source-by-Source Match Analysis
Each match links to the source page, so you can open it and compare the passages yourself.
What It Can’t See
Paywalled journals, private documents and offline sources may not be searchable, so matches from them can be missed.
Frequently asked questions
It's the share of your text that didn't match any source the provider found. A lower score means more of the passage overlaps with existing content and is worth reviewing. A high score isn't proof of originality — it only covers sources the provider can search.
Yes. Alongside the overall score you get a list of matching source URLs, each with its own match percentage, so you know where to look.
You can check up to 150,000 characters in a single scan.
Yes, within the free tier: 3 free scans in total, shared across all five tools (not per day or per month). No signup needed to start. Paid plans include a plagiarism word allowance; see the pricing page.
It can only find matches in sources the third-party provider can search, mostly publicly accessible web pages. Paywalled papers, private documents and offline sources can be missed, and quoted or properly cited passages still count as matches.
Plagiarism checking looks for text copied from existing sources; AI detection estimates whether text was machine-generated. They answer separate questions — text can be original but AI-generated, or human-written but copied.
It depends on text length and the provider's response time. Web-source checks are slower than our other text tools, so keep the page open until the result appears.
Yes. You can upload a .txt, .md, .docx or .pdf file up to 8 MB; the text is extracted and checked the same way as pasted text.