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Free AI detector for PDF — native .pdf upload, no copy-paste.

The free tier on TextSight lets you upload a .pdf directly through the same officeparser v7 file-extract endpoint that Pro uses, with 3 scans per day and up to 5,000 characters per scan. No credit card, no trial timer, no paywall on the result page. Drop a finished PDF into the dashboard, the text layer is extracted server-side, paragraph structure is preserved on text-extractable PDFs, and the classifier returns a 0 to 100 Authenticity Score plus sentence-level highlights on the file you actually have. Eleven file formats accepted from one endpoint, free included.

Scan a PDF free See the 4-step workflow
3 scans/day free 5,000 chars per scan Native .pdf upload
Pricing

Free is the whole pitch.

Free tier with no card, no email. Paid tiers billed in USD with yearly billing saving 25%. Full details on the pricing page.

Starter
$7.49/month

Billed $89.88/year, Save $30

For students and light writers checking PDFs a few times per day.
  • 20 scans / day
  • 20,000 AI rewriter words/mo
  • 11-format file extract
  • Email support
Get Starter
Pro
$14.99/month

Billed $179.88/year, Save $60

For dissertation writers, freelancers, and serious daily PDF users.
  • Unlimited scans
  • 50,000 AI rewriter words/mo
  • File and URL upload
  • Priority support
Get Pro
Business
$29.99/month

Billed $359.88/year, Save $120

For agencies and small content teams running shared PDF workflows.
  • 100,000 AI rewriter words/mo
  • REST API access
  • 5 team seats
  • White-label PDFs
Get Business

Yearly billing saves 25%. View full pricing →

How it works

Four steps from .pdf to sentence highlights.

The free path is intentionally identical to the paid path. A writer arrives with a finished PDF, and the workflow skips every step that a copy-paste would force, on free and on Pro alike.

1. Upload the .pdf

Open the dashboard at app.textsight.ai and drop the file directly onto the scan area, or click the upload control and pick the file from a folder. The endpoint accepts PDF natively alongside ten other formats on the free tier. There is no plug-in to install and no browser extension to authorise. A typical 4 to 5 page PDF reaches the server in under two seconds on a normal home connection.

2. File extract runs server-side

The file-extract endpoint built on officeparser v7 pulls the selectable text layer from the PDF, normalises character encoding, and reconstructs paragraph boundaries on text-extractable files. The endpoint is extract-only and does not burn a separate detection quota; the extracted text feeds straight into the classifier. The textarea then fills with what the classifier will read, so you can sanity-check the extraction before hitting Scan.

3. AI score returns in about 30 seconds

The same classifier that runs on Pro scores the extracted PDF text. The headline is an Authenticity Score on a 0 to 100 scale with a band classification (Likely Human, Mixed, Likely AI). No countdown timer, no advert, no upgrade interstitial blocking the result. The score appears in roughly 30 seconds for an essay-length file.

4. Review sentence-level highlights

The result panel colours each sentence by AI likelihood. A student knows which paragraphs to rewrite; a freelancer knows which lines a client probably drafted with ChatGPT. Sentence-level evidence beats a single document-level verdict. On free you also see the top AI tells the classifier flagged. Re-scan a PDF after editing to confirm the score moved.

What free buys you

What the free tier actually gives you on PDF.

Free on TextSight is not a trial timer. It is a real working budget for PDF detection that fits the most common one-off use cases.

3 scans per day, 5,000 characters per scan

The free quota is three full PDF scans per day, each up to 5,000 characters of extracted text. For a standard text-layer essay that is roughly a 4 to 5 page chapter per scan. The daily budget resets at midnight UTC, so a one-PDF-per-day workflow runs forever on free. Longer PDFs split into chapters or sections to fit the per-scan ceiling, and each chunk uses one of the three daily slots.

Native .pdf upload via the same endpoint Pro uses

Free users hit the same /api/file/extract endpoint that Pro users hit. The path is officeparser v7, eleven formats accepted, paragraph structure preserved on text-extractable PDFs. There is no separate slow queue for free and no upload-format restriction. Drop a PDF, watch the text appear in the textarea, hit Scan.

Sentence-level highlights, not just a single score

Free returns the same sentence-by-sentence colour map as Pro. A 30-page chunk that scores 62% AI overall is useless without knowing which sentences caused it. The free tier shows the exact lines, which is what makes the result actionable for a student before submission or for a freelancer screening a client document.

No card, no email, no paywall on the result

The first scan is anonymous. The Authenticity Score, the band, the sentence highlights, and the top AI tells all render inline. Nothing is greyed out, blurred, or hidden behind a "subscribe to view" overlay. The product is funded by paying Pro subscribers, not by advertising on the result page.

PDF use cases

Five PDF jobs that fit inside the free budget.

Three scans per day at 5,000 characters per scan covers a surprising amount of real PDF work. Five patterns we see most often from free users.

Student essays before submission

You wrote an essay, exported to PDF, and want to see how a detector would score it before Monday morning. A 4 to 5 page chapter fits inside the 5,000 character per scan window, and three scans a day covers the standard "draft, revise, final" rhythm. Free tier is the right tier; no account needed for the first scan, no card.

Contracts and legal drafts that arrive as PDFs

A counterparty sent over a draft contract as a PDF. Run the executive summary through the free PDF detector to see whether the boilerplate language reads as ChatGPT-generated. Most contracts have a few load-bearing sections; you can scan three of them on free in one sitting, and the sentence-level highlights tell you which clauses to read carefully.

Research paper excerpts you downloaded

A research paper feels off and you want to settle the hunch. Lift the abstract and a body section into a 5,000 character chunk, run it through the free detector, and the score plus highlights tell you what to do with the citation. Free is enough for the occasional sanity check; if you are reviewing for a journal you probably want Pro for unlimited scans.

RFP responses, pre-submission and post-receipt

RFP responses are increasingly drafted with ChatGPT assistance and buyers want to know how much. Upload the executive summary or pricing rationale section, read the band, and the audit is done in the time a manual read of section one would have taken. On the sell side, run the same pass as a pre-submission sanity check before the document goes out.

Downloaded articles you suspect are AI

You found a PDF white paper online and the prose feels off. One quick scan tells you whether the suspicion is justified. No reason to buy a subscription for one curiosity check; free is built for exactly this shape of one-off question.

PDF format honesty

What free can and cannot extract from a PDF.

PDF is a layout-preserving container rather than a semantic document format. Being upfront about what extraction can and cannot do matters more on PDF than on plain text, because the same .pdf extension covers wildly different file internals.

Text-extractable PDFs work cleanly on free

Most modern PDFs contain a selectable text layer alongside the visual layout. The free file-extract endpoint pulls clean characters from these files; paragraph structure survives, sentence boundaries survive, and the classifier scores the result identically to a paste. Standard contracts, exported Word documents saved as PDF, journal preprints, RFP responses, and report exports almost always fall in this category. The fast way to check: open the PDF in any reader, hit select-all, and watch the text highlight cleanly. If it does, the file is text-extractable.

Scanned image PDFs need OCR first, on free and Pro alike

A PDF run through a flatbed scanner or built from phone photos contains pixels rather than characters. The file-extract endpoint receives an empty string and returns nothing useful. The honest position is that scanned image PDFs need OCR pre-processing before upload, rather than claiming a built-in OCR layer that does not exist on the TextSight side. Most modern PDF readers offer an OCR action under the file menu; Adobe Acrobat, Apple Preview, and ABBYY all handle this job well. Save the searchable PDF and upload that.

Complex layouts may lose paragraph structure on either tier

Multi-column journal articles with floating figures, multi-page tables, footnotes, and sidebars are the hardest case. The classifier still scores the extracted text correctly on free, but the visual reading order on the result may not map back to the original page order. For thesis chapters, contracts, RFP bodies, and report exports the structure usually survives; for dense journal articles a sanity check against the original PDF is worth running before acting on the score.

Honest upgrade path

When free stops being enough for PDF.

Free is built to be useful for the one-off question, not to be a paywall teaser. There is a real point where Pro starts to make sense, and we are upfront about where that is.

You hit the 3 scans per day ceiling regularly

A teacher reviewing 20 essays a week, a freelance editor running five client PDFs through, or a hiring manager batching 30 resumes will burn through the daily 3-scan budget within an hour. Pro lifts the cap to unlimited scans within fair use, and the per-scan character ceiling lifts with it.

Your PDFs are routinely over 5,000 characters per chunk

Free splits long PDFs into 5,000 character chunks, each consuming a daily slot. For a dissertation chapter or a 20-page contract that gets tedious fast. Pro removes the per-scan ceiling so you can run a full chapter in one upload.

You want unlimited AI rewriter rewrites on flagged sentences

Free includes a limited AI rewriter budget. Pro gives you 50,000 AI rewriter words per month at the Pro tier, enough to rewrite a full PDF in one sitting if a paragraph scored as AI. The AI rewriter feeds straight back into a re-scan so you can confirm the score moved.

Pricing the upgrade honestly

Pro is $19.99 per month monthly or $14.99 per month billed yearly (a 25% yearly discount), with no annual lock-in. If you find yourself hitting the free daily 3-scan ceiling three days in a row, that is the honest signal to upgrade. Until then, free is the right tool.

FAQ

Free AI detector for PDF frequently asked.

Is the free tier really free for PDF scanning?
Yes. The free tier on TextSight gives you 3 scans per day with up to 5,000 characters per scan, and the .pdf upload path is available on the free tier at the same quality as on Pro. No credit card, no trial countdown, no paywall on the result page. You can land on app.textsight.ai, drop a PDF in, and read the Authenticity Score and sentence-level highlights without signing up first.
Can I upload a .pdf directly on the free tier, or do I have to paste?
Direct .pdf upload is on the free tier. The file goes through the same officeparser v7 file-extract endpoint that Pro uses, the text layer is pulled server-side, paragraph structure is preserved on text-extractable PDFs, and the extracted text feeds straight into the classifier. There is no separate, slower free queue and no upload-format restriction on free.
What counts against the 3 scans per day and 5,000 character per scan limits?
Each scan, whether by paste or by upload, consumes one of the 3 daily scans. The 5,000 character ceiling applies per scan, so a long PDF needs to be split into chapters or sections to fit. For a typical 4 to 5 page text-layer essay the 5,000 character ceiling is roughly the right size. The daily 3-scan budget resets at midnight UTC.
Does free do OCR on scanned image PDFs?
No. TextSight extracts text directly from PDFs that contain a selectable text layer, which is what almost every modern exported PDF uses. Scanned image PDFs and phone-photo PDFs carry no embedded text and need OCR pre-processing before upload. Run the file through any OCR tool first, save the searchable PDF, and upload that. The free tier handles the resulting text-extractable PDF cleanly.
Will complex PDF layouts keep their paragraph structure on free?
Paragraph structure is preserved on text-extractable PDFs that use a standard single-column or two-column body layout, on free and on Pro alike. Complex layouts with floating figures, multi-page tables, footnotes, or sidebars may lose some paragraph structure during extraction because PDF is a layout format rather than a semantic document format. The classifier still scores the extracted text correctly; a quick visual sanity check is worth running on dense journal articles.
Which PDF use cases fit inside the free 3 scans per day budget?
A student doing a one-off paper check before submission, a freelancer vetting one client brief, a researcher checking an excerpt of a paper they downloaded, an RFP bid lead doing a pre-submission sanity check on the executive summary, and a casual reader running a downloaded article through to settle a hunch. The common shape is one to three PDFs a day, each fitting in the 5,000 character window. Heavier workloads belong on Pro.
Is the free PDF scan result identical to a Pro scan?
Yes. The same classifier runs on free and on Pro. The 0 to 100 Authenticity Score, the band classification, the sentence-by-sentence colour map, and the top AI tells all render identically. The only difference is the daily scan ceiling and the 5,000 character per scan window; the result depth is the same.
When does it make sense to upgrade to Pro for PDF scanning?
Upgrade when you routinely hit the 3 scans per day ceiling, when a PDF you need to scan exceeds 5,000 characters per chunk and you want unlimited per-scan length, or when you want unlimited AI rewriter rewrites on flagged sentences. Pro is $19.99 per month monthly or $14.99 per month billed yearly, with no annual lock-in. A one-off paper check or single client vet is enough on free.
Related

More PDF and free detector guides.

Scan a PDF for free. No card, no email.

3 scans per day, 5,000 characters per scan, native .pdf upload via the same officeparser v7 endpoint that powers Pro.

Scan a PDF free See pricing
3 scans/day free · 5,000 chars per scan · Native .pdf upload