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Originality.AI vs PlagiarismCheck.org

Two fact sheets from our own research, side by side — pricing, platforms, API access and status re-checked by us rather than quoted from the vendors. Originality.AI starts at $14.95, PlagiarismCheck.org at $2.08. Both ship a public API.

Originality.AIAI-text and plagiarism detection built for publishers and agenciesPlagiarismCheck.orgSimilarity report and AI-text detection in one submission, wired into the usual school LMS platforms

Side by side

FactOriginality.AIPlagiarismCheck.org
CategoryAI Detection & HumanizersAI Detection & Humanizers
Pricing modelPaidPaid
Starts at$14.95 month$2.08 month
Public APIYesYes
PlatformsWeb, Chrome Ext, APIWeb, Chrome Ext, API
CompanyOriginality.AIPlagiarismCheck.org
Launched20222015
Last verifiedSep 6, 2026Sep 6, 2026

What our research says

Originality.AI

The detector to pick if you are a publisher or agency policing freelance output at volume, because the team history and writing replay matter more than the raw score. Do not use it to accuse a student; no detector is accurate enough to carry that weight.

Pros

  • Credit model is legible: 100 words per credit, no hidden weighting
  • API on the higher tier makes batch pipelines possible
  • Chrome extension works inside Google Docs, where the writing actually happens
  • Writing replay from revision history is process evidence, not just a score

Cons

  • Monthly subscription credits expire, so a light month is wasted spend
  • The jump from $14.95 to $179 a month is a steep single step
  • False positives on heavily edited or non-native English writing are a documented hazard across every detector
  • Accuracy benchmarks are largely vendor-run

PlagiarismCheck.org

The selling point is that one submission answers both questions a teacher has — was this copied, and was this generated — instead of running two services. Ten years of operation and real LMS plugins put it ahead of the many single-page detectors that appeared in 2023. Treat the accuracy claim with the scepticism every AI detector deserves: the underlying signals are statistical and non-native writers get flagged disproportionately across this whole category.

Pros

  • Plagiarism and AI detection run on a single upload rather than two separate tools
  • Sentence-level output shows which passages triggered the score, not just a document percentage
  • Genuine LMS integrations across seven platforms, plus a Google Docs add-on and Chrome extension
  • OCR handles scanned or photographed submissions
  • Documented API for business use

Cons

  • The published '99% accuracy' figure is the vendor's own and is not independently verified
  • Institutional pricing is quote-only; the pricing page shows no numbers at all
  • No company jurisdiction is disclosed, which matters for student-data processing
  • AI detectors as a class produce false positives on formulaic and non-native writing

Which one fits

Choose Originality.AI if you need

  • Content agencies auditing freelance submissions before they pay for them
  • Publishers sweeping large archives for machine-written pages
  • SEO teams screening acquired, syndicated or outsourced content

Choose PlagiarismCheck.org if you need

  • Teachers and departments already inside Canvas, Moodle or Google Classroom
  • Editors who need a similarity report and an AI-likelihood read in the same pass
  • Institutions that need OCR because submissions arrive as photographs

More comparisons

All PlagiarismCheck.org alternatives →Browse all AI Detection & Humanizers →