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Online plagiarism checker

Check whether your text is original

We compare your text against real web sources and show which parts match — with the sources.

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Online plagiarism check

A plagiarism checker that shows you why, not just a percentage

Most free plagiarism checkers hand you a single number and never explain where it came from. Pontbot works differently. It searches the public web for the most distinctive passages of your text, downloads the pages it finds, and compares your writing against them word by word. Only text that actually appears in the source counts as a match.

That means every match comes with evidence: your sentence and the source text side by side, with the overlapping words highlighted. You can show it to your supervisor, and you can see exactly where to rewrite, add quotation marks or cite.

How the plagiarism check works

Four steps from pasting your text to citable evidence.

  1. 1

    Paste or upload

    Paste your text or upload a .docx, .pdf, .txt or .md file. We extract the text from the document automatically.

  2. 2

    Search the web

    We split the text into overlapping passages aligned to sentence boundaries and search for the most distinctive phrase in each one. Generic filler sentences are skipped.

  3. 3

    Download and measure

    We download the pages we find, HTML and PDF alike, and measure the word runs that genuinely overlap. The percentage is not an estimate from a language model.

  4. 4

    Results with evidence

    You get the similarity score, the sources, and for every match the two passages side by side, plus a short assessment.

Evidence for every match

Your sentence and the source text, side by side

A plagiarism flag is only worth something if you can show it. For every match we quote the passage from your text and the matching part of the source page, with its surrounding context. You do not have to trust the number: you can see for yourself what overlaps.

  • Precise highlighting in your text, so you know which sentence is affected
  • The title, domain and direct link of each source page
  • How much of the passage each source covers, as a percentage

Your text

Our results confirm that during photosynthesis plants convert light energy into chemical energy, which is the basis of this study.

Sourceen.wikipedia.org

The key point is that during photosynthesis plants convert light energy into chemical energy and release oxygen.

Verbatim match: 10 words, verified on the downloaded source page.

Measured, not guessed

A reproducible similarity score with verified sources

The similarity score tells you how much of your text provably matches an online source. The calculation is deterministic: the same text checked against the same sources always gives the same result. For every source we show whether we confirmed the match on the downloaded page or whether the page could not be reached.

  • “Verified”: we downloaded the page and the text really is there
  • “Unreachable”: the hit is real, but the page sits behind a paywall or blocks downloads, so it does not count towards the score
  • Originality score and risk level at a glance

Similarity with online sources

11%

Originality
89%

  • en.wikipedia.org7%Verified
  • nature.com4%Verified
  • researchgate.netUnreachable
Fewer false alarms

We tell copying, paraphrasing and common phrasing apart

Flagging an innocent text as plagiarism is an expensive mistake, so our thresholds are deliberately conservative. A shared run shorter than six words counts as a standard phrase, not copying, and a single quotation does not turn a whole paragraph into plagiarism. Matches are also sorted by type, so you know where action is really needed.

  • Verbatim match: add quotation marks and a citation, or rewrite it
  • Paraphrased match: the source of the idea still has to be credited
  • Common phrasing: a technical term or general statement, usually nothing to fix

Verbatim match

A longer passage identical to the source. Quote it with a citation or put it in your own words.

Paraphrased match

Different words, same line of reasoning and structure. The source must be credited.

Common phrasing

A technical term, definition or general statement. This is not plagiarism.

Who is the Pontbot plagiarism checker for?

Anyone who needs their text to be genuinely their own, and to be able to prove it.

Students before submission

Thesis, dissertation, coursework or essay: find a missing citation or a paraphrase that is too close to the source before you submit, not from your examiner.

Teachers and supervisors

A quick first screening of a suspicious paper, with evidence you can quote. You point to specific sources and passages instead of a black box.

Editors and journalists

Spot copied passages in a freelance article or press release before it goes out under your name.

Content creators and agencies

Check that blog posts, product descriptions and whitepapers are original. Duplicate content also hurts you in search.

Honestly

What the check does not cover

We think a plagiarism checker should also tell you what it cannot see. These limits are stated in your results too.

  • We cannot access closed academic databases such as journal subscriptions or ProQuest, only the publicly available web.
  • We cannot compare against previously submitted student papers. That is the real advantage of systems with their own corpus, like Turnitin. Pontbot is a web plagiarism checker, not a Turnitin replacement.
  • We do not download pages behind a paywall. We still report the hit, but without evidence it does not count towards the score.
  • The result informs your decision; it is not a verdict. Whether a match is a legitimate quotation depends on your citation and the context.

Plagiarism checker FAQ

What most people ask before they submit their first text.

Is the plagiarism checker free?

When you sign up you get 3,000 characters of free credit to try the plagiarism checker and the other tools. One character costs one credit, with a minimum of 500 credits per check. For longer texts and regular use, the paid plans give you a larger allowance. See the pricing page for details.

How long a text can I check at once?

That depends on your plan: 3,000 characters on the free tier and up to 50,000 characters per check on a paid plan. If your text is longer, the interface shows how much of it we will process. A full thesis is best checked chapter by chapter.

How is this different from Turnitin?

Turnitin also works with its own closed database of previously submitted papers and journal articles. Pontbot checks the public web, but shows you the evidence for every match. It is well suited to checking your work before submission; it does not replace your university’s official plagiarism screening.

How do you calculate the similarity score?

On the downloaded source pages we find the runs of at least six words that your text shares with the source. We combine them, counting overlaps only once, and divide by the length of your text. A language model only helps judge whether a match is common phrasing and writes the assessment. It does not produce the percentage.

What does it mean when a source is “unreachable”?

The search found a relevant page, but we could not download it, for example because it is behind a paywall or blocks automated access. We still show the hit, but because we could not verify the match it does not count towards the score.

Which files can I upload?

Word documents (.docx), PDFs, plain text (.txt) and Markdown (.md). We cannot extract text from scanned PDFs saved as images. In that case, paste the text directly.

Am I charged again if I resubmit the same text?

No. If you check the same text again within 24 hours, no further credits are deducted. And if a check fails with an error, the credits are refunded automatically.

What should I do if you found matches in my text?

For a verbatim match, put the passage in quotation marks and cite the source, or rewrite it in your own words and still cite it. For a paraphrased match, crediting the source is what matters most. Common phrasing usually needs no action. Our paraphrasing tool can help with rewording, but the citation is still required.

Check your text before someone else does

Paste your text into the box above. The results show which parts match online sources, and exactly where.

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